TH level DOES matter in clan wars.
After a couple of clan wars, I have come to the conclusion that TH level DOES matter. The main reason is just for the sheer volume of defenses you can get. I don't care if you are a preemie TH 10 you still can have up to 2 IT's AND 3 Xbows. Even at level one they can do considerable damage to troops... even if you have low level walls... which leads me to point 2.
Matchmaking bases on walls is pretty irrelevant. I have seen so many balloon, dragon and hog attacks that using walls as some determiner of the matchmaking process is kind of irrelevant.
All of this is just my .02 so far from what I have seen.
Which side would you rather be on... 10 level 10 TH with level 10/11 walls or 25 level 10 th with a bunch of pink/purple walls??
I am sure they will tweak the matchmaking process at some point once SC collect all the data from clan wars but I think the level of your TH should some how be incorporated into the equation.
Lots of gemmed up th10s have barely attacked,
and they will get matched against other th10s and advanced th9s.
They may be able to hold up defensively, but they will not be able to win on attack, and their weaker clan members will be destroyed.
Th level matters. So does being a premie.
If you rush your town hall and ignore building up the rest of your defenses and armies good luck looting and defending the resources required to fund those high level defenses like xbows and inferno towers. Anyone who does this is in for a world of hurt.
Your premie is also going to have near the weight of bases that give you a garbage war loot bonus in CWs.
p.s. Just competing with the OP for the title of captain obvious.