This team really needs a....

It's not just that teams can succeed with very different compositions of ATs and powersets -- it's that they can succeed in different ways. Not every team that succeeds does so by steamrolling willy-nilly. Sometimes a team uses control, sometimes AoE damage, sometimes numerous competing single-target attackers going wild, sometimes herding, sometimes just buffs itself into invincibility, sometimes carefully picking off and isolating a few enemies at a time, sometimes melting everything with debuffs, and so on. I've even been on an oddball "drop-centered" team using placed debuffs and Trip Mines to do the bulk of our killing.

Variety is the spice of life -- I find it more interesting when I have to adapt a bit to work better with other players' playstyles or their given powersets.

...more non-Brutes, if I'm playing mine at the time. They're stealing my Fury, damn it!

In general, I just want a team of good players (or mostly good), but sometimes it does help to shift one player from primarily DPS to primarily support when going against tough stuff (ie. +3 Vanguard or Longbow on an 8-man team in RWZ).

Example: Last night my 4 blaster (I was one, SK'd on a pre-Shiver DP/ice), 1spines/reg scrapper, 1 Rad/rad def, 1 Nightwidow, 1 SD/FM tank was fighting just such a +3 (mostly Longbow) mission. We had a couple wipes, despite being mostly rather solid players, usually from ambushes. Now we didn't NEED for someone to swap chars to complete the mission. We could easily have shifted tactics to not be facing full spawns at once (via pulls etc.), but that would have changed the rapid pace that many of us very much prefer to play.

I decided that I would switch from my lvl 26 DP/ice blaster to my fairly IO'd Ice/FF troller, and the Nightwidow switched to her Merc/Pain MM. Well, as many of you would expect, things went much more smoothly (and rapidly) after those two swaps. A big part of it was getting mezz protection (from Dispersion bubble) which was absent on 5/8 previously, so the Longbow Nullifiers stun-fest was less of an issue (every-spawn Ice Slick and Shiver didn't hurt either and the agro spreading and support from the MM). We didn't mind making the switches, and the team benefited.

My advice to the OP, is to play what you like to play. That said, try and develop a variety of different ATs to a relatively high level, get them fine-tuned with some IOs (or pick combos that still perform at a high level without them) and have a diverse toolbox of fun available. Most good players/leaders don't care what you bring to the party, though they may suggest 1 volunteer to swap chars, if the team makeup looks particularly vulnerable/low-damage. Almost always a 1 character swap can solve any team tactical issue, and most of the time even that is not necessary.

Bottom line, have fun.

I want teams who just want to have fun. As soon as I start feeling that I'm working instead of playing a game I'll get bored.

I also like a chatty teams with lots of bad BAD puns and jokes when attacking enemies.

I should answer my own question. Low damage teams to me are...

For teams small in size (4 players and down): Teams with 1 or more players who either do not, can not, or will not frequently push their attack buttons.

For teams large in size: Many factors...
1) Teams with those players from above who don't/can't/won't attack
2) Teams that lack a significant amount of aoe damage powers relative to their level (a large team at level 12 with few aoe attacks is normal... at level 50 abnormal)
3) Teams that lack a significant amount of damage buffs
4) Teams that lack a significant amount of enemy debuffs
I'm not saying that teams that have these qualities won't succeed. I am simply saying that teams that have these qualities are generally (key word "generally") low in damage relative to other teams.

I've seen some people mention things like "yeah, imagine if we had 8 emps on the team... it would be so terrible damage wise." I've been on 8 emp teams. I can show you 8 emp teams. There are lots of words to describe 8 emp teams. "Low Damage" are not such words. Perhaps the 8 emps others imagine are the "players who can't/won't/don't attack". The 8 emps I have played with call themselves "a rolling nuke" for legitimate reasons.

Teams with large amounts of Controllers and Defenders really shouldn't be generally considered "low damage". I'm not sure how one could possibly consider such teams "low damage" unless they imagine the Controllers and Defenders as people who "can't/won't/don't push the attack buttons."

Use to be anything really...

But then the difficulty slider came in the picture...

While i don't mind joining random teams, if i have to make mine especially for a tf i'd rather have it as good as it can be. I'm probably doing that TF only for merits so the faster it can be, the better. So i tend to prefer teams with a single tank (and not 4 of them), 2 rather specialized supports (usually kin, rad, FF or emp) then fill in with blasters and scrappers. I prefer defenders over controllers as they tend to be more focused on what helps the team the most (buffing/debuffing) rather than useless controls (at lvl 50), and peacebringers/warshades are way too bad in the hands of the average player to be useful to anything but spawning nictus.

Is it needed ? It isn't, of course. But i prefer to run a TF in 1 hour steamrolling everything and herding maps while having fun than doing it in 2 hours and spending half the time running after mobs flying everywhere or unloading my AoEs in a pack of 3 mobs.

Overall though the only teams i will leave (or kick someone from) are the ones with a very annoying AT, or one that doesn't fit at all with my playstyle.

The ATs i like having around the most are kin and FF defenders. Both of them dramatically increase the fun i have either by providing total safety or a massive amount of damage.

Yeah, asking for player's of Sister Flame's ability is probably asking for too much when considering the "average player".