You didn't sound very keen, but you didn't say you didn't like it.
It's a phenomenon I've seen before, not just with you (and Kieron to a degree) - people playing games just for trophies and achievements. If I'm playing a game and I find 90% of the hidden items on my playthrough it's unlikely I'll replay it so I can get the other ones. I'll do so if it's a great game I was going to replay anyway, but just to get some gamerscore? Nope. I've even seen people buy games they know they won't like, just because it's easy to get all the achievements. It's madness.
Screw that. Play a game you enjoy until you get to the point where you've done everything you want to and you want to play something else - don't play to fulfil some random bloke's criteria for having fully experienced the game.
There's a difference between not being too keen on a game, and totally disliking it...Is it one of my favourite games of all time? No. Is it a game I'd go back to time and time again? No. Was it simply an OK open world game with mostly average elements with a odd smattering of genuine quality/interest? Yes.
My judgement when it comes to games is actually very good...I base that off the fact that I can't even remember the last time I bought a game that I actually hated to the point where I flung it aside and never touched it again...Granted, I've played alot of average games that dissapointed my expectations of them, but that's not necessarily a bad thing...I completed Skyrim to Platinum in 150 hours in a span of almost 2 years...It's a game that I found good to play in small portions, and the best thing about the Platinum is that you don't have to do any senseless grinding for it and just by beating everything the game has to offer, which you would have done anyway, can grab you every trophy in the game.
Levelling grinds are a different matter, though it does depend on a number of things. I reached level on Red Dead Redemption, but me and my mates always used to posse up and either fuck around in free roam having shit loads or laughs or team up and kick some arse online...It was incredibly fun and made me want to reach level 50 for the trophy.
Take a look at my breakdown;
http://psnprofiles.com/SimplySupremeThere's a ton of games there that are nowhere near to fully completed. I haven't gone off these game or anything, I'm just playing other things at the moment, but I wouldn't start rocking uncontronably in the corner of my room to the point of needing medicine if i never completed them, I just like to use trophies as a good measurement of what you get out of a game.
There's a massive difference between a trophy whore and a trophy hunter...Trophy whores will play absolutely anything to get trophies, mostly easy, quick or cheap games, and they avoid lengthy Platinums like the plague...They'll also avoid games they would have usually bought, but don't want them to tarnish their completion percentage because they might be too hard or require too much time to beat.
Trophy hunters just go that extra mile to beat a game beyond standard completion, they don't give a flying fuck about how hard or long the time might be, they just enjoy the game for what it is and try and embrace the extra challenge.
I don't class myself as either of those...I buy games I have a genuine interest in and don't even bother studying the trophy list in any great detail, not do I care how long beating the game would take...10,000 kills on Resistance 2...I ended up getting on 14,000 on that game...500 games on FIFA 12...God knows how many I ended up actually playing...Rank 10 on GTA 4...Legend Rank 5 on Motorstorm, list goes on.
If you enjoy a game enough, trophies don't even become an issue...It's when you hate the game that starts become a problem, and I never have that issue...I love the games I play and the Platinum trophy gives me a convienient excuse to indulge in them further.