I was jesting about 75%. I don't really see a problem with 50%, though. Looking through all of the team battles with stated power levels, anyone below 50% was dog shit.
Raditz (1,200+) vs Goku (416) & Piccolo (408) = weakest link is 34% at most, and they were both properly squashed.
Nappa (4,000+) vs Piccolo (3,500) & Krillin (1,770) & Gohan (981+) = weakest link is 24% at least, and all were squashed regardless.
Vegeta (24,000) vs Zarbon (23,000) & Dodoria (22,000) = weakest link is 91% and the team was posed as able to win.
Vegeta (30,000) & Krillin (10,000+) & Gohan (10,000+) vs Raccoon (~40,000) = weakest links are around 25% and whole team was murdered.
Burta (~40,000) & Jheese (~40,000) vs Goku (60,000+) = both were around 66% at most and both got owned.
Some numbers aren't stated but they're good enough estimates to illustrate the point. It seems that if Goku was in actuality using bursts of 60k, then even two people at 66% of the opponent will be utterly outmatched. Maybe that changes if someone at 80-95% of the opponent joins the duo, who knows.
Following that, if 66% isn't enough, then maybe 75% is decent.
Freeza - 530,000
Vegeta - 500,000
Gohan - 400,000
Krillin - 400,000
It makes Gohan and Krillin much stronger than most people would usually give them credit for (especially Krillin), and puts them closer to Vegeta than I'd personally go, but I don't see a huge problem with it. And by result of their bolstering, people who have Piccolo above them pre-Nail would also have to put him near Vegeta, which makes his fear of suppressed Freeza somewhat hard to believe, unless they also boost that level of Freeza, but then that makes his power-up seem miniscule.