I think the whole "tier 3" thing is stupid. Whoever thinks TB is weak in 2v2 Cata make me laugh. I'll agree that DA and Reg are the two weakest, but TB is Tier 2 to begin with, and I'd say he's stronger in 2v2 Cata than 3v3 Cata. So yeah.
Rather than a complicated point system, I think you should group it by tiers:
1- Oak, Erebus, UB, Rook
2- Sedna, Queen, Occulus, TB
3- Reg, DA
Pick 1 + 3 or 2 + 2.
Of course, the fact that Rook and UB couldn't be monk-supported (all T3's are Assassins) until priests come out, this limits their effectiveness by a lot... you could do something like this
1- Oak, Erebus,
1.5 - UB, Rook
2- Sedna, Occulus, TB
2.5 - Queen,
3 - Reg, DA
The rule is that you must have at least 4 points.
Although Queen is plenty strong, and she's good in 2v2 where she can't be focus-fired quite so easily and Armor debuff with Ground Spikes is huge, she lacks an Interrupt, which causes a lot of stress. Plus, you are more poor in a 2v2 game than a 3v3 (you have 2/3rds the gold income to purchase cit.upgrades which comes out of your items. Plus, less kills) means that she cannot get her nice items as early. Occ has the same problem, where I would normally consider him tier 1.5. So he drops to 2 but you could keep him at 1.5 if you think that he should stay there. It also prevents a Sedna + Occulus combo which would be really strong.
This gives a lot more variety in Demigod selection (right now it is pick Erebus or Oak, then pick TB or Reg. That's a whopping 4 combos!) Now we can get Queen + UB combos or Queen + Rook, which should both be strong while not overpowering and that has good synergy. We can go TB + Sedna, we can go Oak + Reg. All those combos have good synergy and the possibility to be competitive against the majority of other matchups, while I can still see a Reg + Oak combo beating a Queen + UB at the same time.
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Also, since when is Pacov the official judge, jury, and executioner of the demigod forums? We'll have this tourney when we're damn ready. I understand the need to "move things along" but a tourney with 3 teams is not going to be all too exciting and I still need to prod Thundercles with a pokey stick.