It seems that G0-T0 is the forgotten squadmate in KOTOR2. I guess that a big chunk of the dislike for him is how redundant he is as a Squadmate when compared to HK-47 or T3. Scorchy pretty much sums it up in his LP.
https://lparchive.org/Knights-of-the-Old-Republic-II/Update 31/
https://lparchive.org/Knights-of-the-Old-Republic-II/Update 32/
"The problem with Goto in combat situations is that he's horribly designed in the context of the game. He's less combat oriented than HK-47, and has less skills than T3-M4, so the min/max streak in people would cause them to take either one of the other droids. His main strength is his ability to dominate other droids into fighting for the other side, which is a great ability. Unfortunately about 90% of the droids in the game are on Nar Shaddaa, and we get Goto after that planet is finished, so that ability is totally useless. He's also the only droid who can stealth and he can't trip off mines (seeing as he floats), but... neither stealth or demolitions are class skills for him. All in all he's quite frustrating to use. Still, give him some good pistols and a plasma thrower like this and he'll kick as much ass as anyone else.
The other problem with Goto is that he's a huge fatass and it's hard to see around him when you're controlling. There's also a couple of size jokes in the game as well. HK-47 calls him 'fat one' all the time, and - I don't know why I'm mentioning this - you know those interactions Goto has with Bao-Dur's Remote? According to the voice directions for Remote, he's making fun of Goto for being so big and fat; that's what all the beeping is about."
What else do people not like about him? His personality perhaps, or his backstory?