Lordaeron has buffed content, which makes prot warr a poor choice, yes you can play it, but it requires a lot of gear and great knowledge of the spec, prot pala and bear are far better here. The only time I've seen prot warr tank is in icc10 and that guy not only knows how to play, but has tons of gear from togc and icc25
EDIT: Which he got by dpsing
I play prot warrior (level 53 at this moment) and we, as a guild, plan to build ourself up with Naxx, Sanctum, Eye of the Storm, etc. first, then starting Ulduar and ICC. Just for the challenge and fun that comes by raiding with friends.
Reading all this crap about prot warriors beeing underpowered is putting a dent in my motivation but we'll try anyhow.
I'm no expert on prot warriors but I have played on wotlk realms for the past couple of years... The way I see it, blizzard realized that in vanilla and tbc they had made certain classes/specs much better than others in PvE. Afaik prot war was the best tank for these expacs and the other tanks were kinda gimp/barely viable. Seems like in wotlk they wanted to buff classes who were gimp the past 2 expansions and so prot war had to become the more gimp tank. They are still viable just overall not quite as good as the other tanks. Reminds me of how ret pala was utter **** in PvE and barely viable in PvP in vanilla/tbc then buffed in wrath to be a strong spec for both.