Rogues, including bards, are not scaling well at higher levels right now. That may change but personally I wouldn't put all eggs in one basket. Really depends what your goals are at end game.

For pvp, mages are pretty sick right now. I'd consider 2-4 mages and 1-2 clerics as a team if pvp is the main goal.

If you're mostly pve then I wouldn't worry about the IWT. Follow in this game works very well and melee range is pretty wide angle. I've been running a melee team that's basically paladin, rogue, bard, 2 clerics. I flipflop one cleric to spell dps or melee dps or extra heals for dungeons. Working great so far. I've tried ranged dps specs and they're harder to manage and position and get steady dps than the melee with my team, especially for AE which is what I'd say I use 90% of the time. I also don't think the melee team is all that bad in pvp with how well follow works, and the fact you can just stick ranged attacks in your combo macros that will fire if target is out of melee range.

If I was to do all ranged again, I'd rather have mages in the mix than rogues now.