multiple shield slams on 1 enemy? keep in mind there is an immunity timer once stunned, so it's not like you can chain stun with slam over and over. in today's RvR, whether it be 8v8 open field or tower camping or keep siege, you don't have the necessary components to do well. No CC, no real dps (even with 2h pallys), no intense targetted heals (keep in mind that a good caster can hit you for anywhere from 250-900 depending on resists/relics every 2-3 seconds, not to mention aoe insta stunning mids. Your heal chant will simply not keep up), ghetto rez. Even with det5 tanks you will drop pretty quickly.
I imagine an all pally guild will decently against a stealth group or any other all melee. But throw in a bard or a skald or a healer/druid and you won't kill your target fast enough without losing 1 or 2 of your own ppl (this assuming you've got the assist train on the healer).
If you truly want a good 8 man alb group, roll a s/s pally, a merc, 2 clerics, a sorc, a minstrel, a matter cabby, and a fire or ice wizard. Merc and Pally need battlemaster ML8 for bodyguard, and you're golden. I honestly can't think of a better group right now. Especially if your sorc is at the top of his game.
PvE wise, I can assume you'd do... fairly well. As long as you know how to make a Main Assist and learn how to use him.
Do heal chants stack?