Temple High Guard and all the other promos are available to play on OCTGN, for those who aren't aware. You can give them a shot on there before deciding if you want to buy them off eBay.
On topic, I really appreciate the discussion in this thread. @Arlemus, I think that +5 health is enough of a bonus that it's worth putting on any creature, efficiency aside. Also I'd much rather have a 7 dice piercing 1 attack than a 4 dice piercing 1 attack, know what I mean? Yes the cleric is more efficient for the same bonuses, but in the end you have an average creature when you could have had a wrecking machine. That's how it looks to me anyway.
I thought that too at first, but the main problem with that is that you have to pay
more than double the cost of a HA cleric for a HA Knight (7 mana vs 17 mana).
That's a pretty huge mana sink, which isn't
inherently bad, but (like most pet abilities) you're paying more mana for the same level creature. This means creature control spells that pay based on level are now more effective on your massive investment, which isn't good. It happens to be very efficient to pay 6 mana to sleep a 17 cost creature, that's only about 1/3 of your investment to shut it down, and having to wake it up when you're already starved for actions isn't something I'm too fond of
.
No one really bothers to control a HA cleric, from my experience. I've never had anyone sleep one, it's just usually not a good play. Initially investing in a HA cleric also leaves plenty of mana to buff the Priest, which is more important than having a HA anyway. Paying for a massive 17 cost Knight doesn't leave you much to buff up #1.
Also, I'd much rather have a HA cleric and just summon a Knight after, if needed. In doing that, you're getting the HA buff for minimal cost (2 mana) and diversifying your investments. Yeah, it means you need to spend a full action summoning a knight, but now your HA has more targets to avenge off of and isn't so easily controlled.
They way I think about it, it doesn't really matter which creature the HA is on as long as it's on one of them. It's 5 hp and +2 melee and 1 pierce no matter what, so I might as well pay as little for that as I can and if I need another creature then I need another creature
. I mean, a HA knight can wreck face, I've seen it happen, but most wise up and pick apart that huge investment.
TL;DR: Diversify.