This discussion isn't a new one.
*edit* to add list of links to similar discussions, some dating back to 2013 or earlier:
http://forum.arcanewonders.com/index.php?topic=15570.0http://forum.arcanewonders.com/index.php?topic=15370.0http://forum.arcanewonders.com/index.php?topic=13773.0http://forum.arcanewonders.com/index.php?topic=14864.0http://forum.arcanewonders.com/index.php?topic=12994.0While it would be great to have a large data set for detailed statistics, we only have a few tournament results to suggest that the Wizard is indeed the most powerful mage to some degree. The best players either play the Wizard themselves, or build their spell books specifically to deal with Wizards, both because they're expected to be prevalent in competition and because a Wizard is pretty much always a tough match-up for every other mage.
Looking at it the other way, in a healthy meta in an asymmetric game, any mage and spell book will have some good match-ups and some bad match-ups. It seems that well-constructed Wizards have many good match-ups, maybe a few even match-ups, and generally the "toughest" match-up that a Wizard needs to plan for is another Wizard. All other mages have good and bad match-ups against other mages, and as far as I can tell, they all have a bad match-up against a Wizard and thus need to build and develop strategies specifically for facing Wizards. But most evidence comes from limited tournament data and anecdotal evidence that might be biased by "group think" and/or sample bias (e.g. if half of all players play Wizards, and most top players play Wizards, then it shouldn't be surprising that Wizards tend to dominate) and confirmation bias.
Instead of statistics, we can also look (again) at what many perceive to be the "unfair" advantages of Wizards, and compare them to other mages:
1) high channeling of 10 (equal to some other mages, but a distinct and obvious advantage over any mage with channeling of 9);
2) cheap access to more channeling increasers than any other mage (up to 6x Mana Crystals, Moonglow Amulet, Harmonize);
3) the highest channeling creature spawn point - unless the opposing mage intentionally casts fewer spells in order to minimize it (which would probably be just as advantageous to the Wizard due to higher channeling);
4) an innate defensive ability that is always useful, as opposed to highly conditional abilities that either don't get used often (sometimes not even in every match) or need to be built around;
4b) the most obvious counter to this defensive ability would be to swarm the Wizard with lots of creatures/attacks, since Voltaric Shield only negates damage from one attack per round, but Wizard also has cheap or exclusive access to most of the best anti-swarm spells (Suppression Cloak, Mordok's Obelisk, your choice of zone attack spell(s) - e.g. Chain Lightning/Electrify or Hail of Stones or Ring of Fire/Firestorm) so that strategy tends not to be viable; oh, and if the opponent instead tries to use one very heavily buffed creature to overcome your Voltaric Shield (plus a "wasted" attack to turn it off first), you have Banish to deal with that;
5) the best innate attack in the game (ranged + ethereal, ignores guards, can be used with Quick Cast, only costs 1 mana which means if you use it every turn you're on par with mages who don't spend mana to attack but have innate channeling of 9; or think of it like an attack spell you always have access to in addition to your 2 chosen cards and possibly Mage Wand or Arcane Wand);
6) cheap access to the most staple spells (Dispel, Seeking Dispel, Teleport, Nullify, Jinx, Mage Wand, Arcane Wand), leaving more room for specialized spell book building (e.g. cheapest "base" cost);
7) cheap access to an element of your choice (tied with Warlock and Warlord and better than all other mages, except you can choose which one you want - e.g. pick "water" for more staples for maximum efficiency, etc);
8) regular cost access to every other school (e.g. all the Nature enchantments; any creature(s) you might want; a toolbox of attack spells for your Wizard's Tower - see below);
9) cheap access to powerful hard-to-kill arcane creatures with strong abilities;
10) Wizard's Tower = NOT zone exclusive, NOT Epic familiar conjuration (e.g. can protect a Battle Forge or Mordok's Obelisk or whatever) that is almost like putting a second Wizard in play.
Basically, if there's something you want to do, the Wizard can probably do it equally well or better than any other mage. OK, that's not really true: he can't pump out a creature swarm like a Beastmaster or Necromancer, nor is he as efficient as a Dark Mage at Damage Over Time, nor as efficient as a Holy Mage at healing, but the Wizard doesn't need those when he can kill you before DOT has a chance to factor in and before you can do enough damage to make him need healing (e.g. wins a damage race) or can deal with swarms to render them irrelevant. When you add up all the things the Wizard does better than another given mage (and that a Wizard generally doesn't do anything worse - e.g.
no drawbacks relative to any other mage), it seems obvious that the Wizard would be the best choice most of the time, and that you'd be putting yourself at a disadvantage by playing any other mage. You'd have to work hard to overcome another mage's disadvantage(s) through spell book building and/or clever play and/or luck, trying to find a way to surprise your opponent to gain other advantages.
(This partly explains how a creature swarm Beastmaster was able to win a high-profile tournament dominated by Wizards last year: nobody expected a swarm because it had been written off as "not viable" so few packed the obvious counters, and in a match that could easily have gone the other way (in favour of a Wizard), a key Chain Lightning attack roll fizzled, allowing the swarm to survive and win.)
As for a "fix," I agree with a lot of Sailor Vulcan's comments, especially that nerfing Wizard's Tower merely takes away one of the Wizard's tools but doesn't change any of his other advantages (e.g. doesn't fix the Wizard himself). He can still pack a toolbox of attack spells including any elemental spells that come out in the future, and still has his high channeling, innate Arcane Zap attack spell, innate Voltaric Shield defense, etc. That isn't to say Wizard's Tower shouldn't see errata (e.g. at least make it Zone Exclusive and/or Epic and/or add a cost to change spells) - just that it might not fix the problem where the Wizard is the "best" competitive mage.
I think the Wizard would still be on par with other mages if all unchosen element schools, and possible Nature, cost triple. This would remove the "I have all the good spells" toolbox that he can currently pack for much cheaper than any other mage. I could also see him still being competitive if his Arcane Zap cost as much as 3 mana (e.g. becomes more like a reasonably priced attack spell he always has with him, rather than a practically free attack spell)... but I doubt that mana-taxing Arcane Zap on its own would do much without also sbp-taxing the out-of-school attack spells.
As for the poker analogy... as a (former?) avid poker player, I had to shake my head. Poker is a symmetric game (assuming you play many complete orbits of hands in a session). Mage Wars is inherently an asymmetric game. If the only mage anyone could play was the Wizard - or taking it to an even greater extreme, if everyone had to play the same spell book - then the poker comparison would be valid. However, the perceived handicap of any other mage vs. Wizard is more like playing Texas Hold'em where one player always has connected hole cards (e.g. 67s or JQo) and the other player always has a pocket pair (e.g. 55 or KK). The player with connected cards will win some hands, and might be able to play well enough to win a large enough share of hands and large pots through smart play (e.g. knowing when to fold; knowing when to bluff; correct bet sizing; etc) and even come out on top in a given session, but on average, the player who always has a pocket pair will win more hands, and if he's equally competent, should win more money in the long run. That would be an unfair asymmetric game, not due to the rules of the game itself but due to the added asymmetric component being unfair... which is what we're talking about when we say the Wizard is inherently at an advantage vs. other mages.