Nihil -
You're right, that probably is an intrinsic flaw. I've been debating it for awhile with some of the other rules guys. There've been a few different opinions about how to do end game - one is just a system where the players decide or else get a double loss. This works well for some games, but a lot of players feel like this isn't concrete enough for a competitive system. On my end, I love it because of the elegance - you two are in the battle, if you don't know who's winning, figure out a way to decide. However, I completely understand that for many players, this defeats the purpose of having played the game to begin with if you're just going to "decide" who wins at the end.
Time limits definitely favor blitz spellbooks as well, that's true. And they also favor Priestesses who can heal up at the very last minute. I agree with you there.
As for the OP - this is another one of the hard questions - we're getting feedback from all of our players, and its pretty varied. Long game times for people who have just recently started playing Mage wars are pretty normal we're finding out, and we're doing things to help this (the Apprentice Mode Spellbook is one thing, and we're trying to find a way to package the cards in future printings so that they come pre-sorted, this should at least help setup time).
But we're also getting a spectrum of player responses on game times as well. We're getting some 45 minute players, some 75 minute players, and some much much longer times. The experience ranges a lot as well. We've got expert long-term players that have a wide range of experience in several titles that say their games take long, and we've got newer players who say they just blast through it.
Honestly - when I have numbers like that, all I can say is that your mileage may vary on game time. I do believe game time shortens over multiple plays. But that belief is just based on my own personal experience, and then the experience of the other playtesters I've seen around me.
I don't think long game times should be attributed just to new players or to inexperienced players or unaggressive players as I feel like I've seen enough feedback at this point to say "some players game just take longer."
However, I think you guys know that I'm always open to feedback and suggestions and I always try to be as transparent as possible. If you see a problem, or are reporting a pattern that you're seeing that seems odd - then I am all ears! Also, if you just want to chat one on one about game time and our plans for OP and how to setup a great system you should always feel free to e-mail me.
Thanks again for the good discussion guys!