if you care about completing games, something that in no way inhibits or diminishes your joy in completing games is a big deal.
So how does someone that gets trophies by hacking affect this at all? You can't complete games anymore because of that?
The only thing that is affected are trophy leaderboards. And those can blacklist people by themselves. Also most of the time those hacks are obvious, so anyone that checks other people's trophy lists will notice. And as soon as it's known - best example duck360 - the one hacking trophies will lose any respect to anyone else - so for him it's actually completely useless to continue on that account. Duck360 still continues (and it's even multiple people playing). I don't see the point, but if he is happy about that, why should anyone bother.
Even that isn't a real problem - i mean come on, as if the top #1 on YGC would be worth anything. And for local trophy leaderboards like here on NeoGAF - anyone that is seen cheating will lose all respect from the fellow gamers - so only an idiot would do so.
Using glitches in games (best examples Uncharted 2+3 multiplayer) - well, the proper way to handle this is to fix the glitches. Banning glitchers won't really solve the problem. They can just create another PSN account in case of a banning - that's a given on a free network. Also you can't be really sure, if the one doing the glitching really did it on purpose or if it was just an accident. I for example spawned into a wall during an Uncharted 3 match. Other people could have thought that I was glitching on purpose, fact was that I wanted to spawn near my buddy and the game spawned me inside a wall.
I can't begin to describe the frustration I'd feel on PS3 to grind away at a very hard trophy or game completion itself for weeks, only to have hundreds of teenagers then hack it and get the Platinum in 2 minutes.
How does this affect you at all? It's obvious which people hacked the platinum (timestamps right after each other) and who did not.
I would even prefer trophy hackers instead of having people not play the game properly because of some freaking trophy (example: Driver: San Francisco - one game mode is actually almost unplayable because of trophy whores) or even worse: trophy boosters that give a shit about people playing the game properly. I have nothing against boosting, IF you do it in a separate room and don't bother people playing the game properly. But I got issues with people boosting AND ruining the game for other people at the same time. That's 10000x worse than anyone hacking trophies by saved games.
And I experienced something similar to yours. I got 100% Space Channel 5 Part 2 and uploaded my save to gamefaqs. Some morons hacked it to get the quite difficult trophies. Got informed via PSN message by someone. I removed the save because of that. But besides using my save, it didn't really bother me that much. It was pretty obvious who hacked and who did not.