First: Beta has a new talent tree up for Paladins. Now I am not going to deeply into it, because it is probably far from finished, but it seems we'll be watching procs a lot more, which I don't like as a tank, procs means chance, so I need to gamble with the the other players present.
Now on to the main dish.
GC has stated that he wants avoidance to matter more then now. One of the things changed is that *gasp* healers have to look at their mana again.
No let me take you back. In the old days of TBC, me first voyages into Karazhan was as Holy (long story). So I actually healed there. I had no add-ons to help me, and I just looked at health bars, and pushing 1 (FoL), 2 (HL) or 3 (HL rank 7). But I got away with reactive healing. Tank (or someone else) took damage, throw a heal at him/her. This meant that I didn't waste mana on healing-not-needed. And still I needed to pop a pot every 2 minutes to keep enough mana for the whole fight.
My Primary spell was FoL, because it was cheap, my second most-used spell was HL rank 7, not the max rank. It was cheaper and filled the gap between HL and FL max ranks. It was all about mana.
Now I also healed sometimes in Ulduar, and my memory of that was very simple. Target tank-->spam Holy Light. Mana-problems? Never, I sometimes had to use Divine plea to get mana back, but I can't remember using a pot.
Now these are two completely different healing-methods, and it also effects how tanks played and geared. If you gear/gem like today, which is pointed towards Stamina and Armor, there maybe a problem. You will take most of the hits, so you need to get healed often, if not always, else you die. Now with infinite mana this is not a problem, healers just spam-heal you, but what would happen with the healers mana, if it wasn't infinite? There would be a good chance that your healer would run oom halfway the fight.
And that's the reason tanks used to look at dodge/parry a lot more in TBC then now. A hit avoided would mean that your healer wouldn't have to heal you, which meant that he had more mana. But there-in lies another problem. If the hits where that big, that 2 would kill the tank, the healers still needed to spam-heal the tank, because you don't know before hand if the hit would land or be avoided. You could cancel the heal just before casting, but imho, that often fails, because of lag or because you took the cast-time to look around to others (or colored ground).
So, for dodge/parry to become important again, healers should again be able to heal reactively, instead of pro-active like now. Because that's how is healed these days, just spam HL, and don't worry how hard the tanks get hit. That would mean that bosses can't 2-shot the tank anymore. A normal hit on a (content-geared) tank should only take of 30% of his health, so healers can react to it, and if the hit is avoided, they don't have to heal the tank.
Back in Kara, I never topped of the tanks, I always had them at around 92%. If I would heal the tank, some mana would be wasted, and the tank had enough health to survive at least two hits. So if he got hit, and was thrown, to say 50%, I could fire off an expensive HL, or use two small FoL. Probably the latter, because another healer would probably also toss a heal, and I could actually save the mana from one FoL. It also opened up the possibility to look at the raid, and use a heal there. If the tank was still above 70%, no heal was directly needed, I could finish of a heal on a DPS orso, and then heal the tank. Chance was he would avoid the next hit, so I had some time, and even if it wasn't avoided, the tank would still be alive and ready to receive some oh-shit heals.
So for the TL;DR version:
If Avoidance should matter for tanks again, boss-hits must be smaller, and the mana of healers should not be infinite.
And for the record, I am still in the mind-set, that my weapon should be enchanted for threat (spelldamage in TBC, agi/crit/hit today), and that one trinket-slot is for stamina, an the other for avoidance, or an on-use avoidance ability.