I have been playing a bit on the 3.2 PTR, and to be honest here, I haven't actually tested an awful lot of changes (like the new raid and 5 man, and the battleground levelling.) But heres my opinion on the upcoming changes anyway:

Trial of the Crusader
At first, I wasn't that interested in seeing this new raid, until I found out that it was going to provide the next tier of content. To me, it just seemed like a few Arena bosses that you had to fight, but with no trash mobs. However, there are rumours that the Scourge are going to intervene in this tournament, and that the rumoured final boss is going to be Anub'arak, the undead king of Azjol-Nerub who we last fought in a 5 man Heroic.

When I first did Azjol-Nerub, I was quite disappointed that Anub'arak had such a minor role to play in Wrath, seeing as he was one of the Scourge to travel with Arthas during Warcraft III. However, if the rumours are true, then there could be an interesting plot twist. Also, I haven't tested any of this raid, but I think it could be good.

Trial of the Champion
As a Hunter currently doing tier 7 content, I think the fact that this dungeon is going to drop item level 200 and 213 items is good, including a decent ranged weapon. However, I am not very interested in this 5 man, although a showdown with the Black Knight could be good. As with TotC, I haven't tested these changes.

Resilience Buff
I have felt like I've taken less damage in PvP. Then again, this could be because I have mostly done PvP with a premade character with full Deadly Gladiator and Tier 8. But I do think that making players take less damage is a good idea, because burst can be overpowered at times.

Battleground Levelling
I think this could be a good change, and if it turns out successful, then it could provide a good alternative to questing which can get repetitive over 80 levels. I haven't managed to test this yet but I'd imagine that it would be a good change.

XP Freezing
I can see two very good effects of this feature:
1) Twinks are separated from levellers, meaning no getting destroyed by twinks with thousands of health, and very powerful enchants/gear when trying to level up through a battleground.
2) The ability to freeze xp gains at a certain level (e.g. 60 and 70) and do old content, since classic/TBC guilds have formed.