Maybe I'm just a sucker, but none of the free roaming Spider-Man games got boring to me. I still play them.
I wouldn't call you a sucker...that doesn't seem appropriate. If you find them fun you just have a different taste or standard vs mine.
In all fairness, I still have not played the ASM2 game. I refuse to shell out money for it. I base my opinion on the many videos I've watched and of course from people on here and some friends that have actually played it. Playing a game can make a difference in viewpoint however what I've seen of it doesn't interest me. Aside from the webswinging and more open world random events, everything else appears to be a downgrade from the first ASM game.
Beenox' ASM game was a lot of fun...initially. Unfortunately that game quickly lost its appeal. The combat was the best part imo. While it wasn't up to par with Arkham it was still fast and fun--kind of like an Arkham-lite. Like taking the fun part and animations from Arkham's combat but leaving the challenge and polish on the floor. And while Beenox did implement some very cool and imo much needed gameplay mechanics, i.e. web rush, perch points, and solving the camera issues, etc. they failed in regards to the open world. If I remember correctly there was only a handful, like 5 or less, of different types of random crimes. But they weren't even random. The same crimes popped up in the same spots as you progressed thru the game and when you completed all of them, there was nothing left to do but swing around. The swinging itself was fun but the lack of physics and webs attaching to structures was annoying as well as a very lackadaisical version of NYC. For me the free roam portion of any open world Spidey game should be the highlight and in this game it became the low point. And with ASM2 they added the nonstop random crimes but they also took a step back by adding cutscenes before and after each one and then adding the hero/menace system was a mistake. Just wanna go for a swing? Oh too bad. Not stopping to help any random crimes eventually puts you into the menace category and you can't even enjoy a swing around the city without some damn robots blocking you. The first ASM was definitely fun at first but after a few hours everything felt like more of the same. No real variation in the enemies, combat upgrades hit a wall, the environments all looked the same, etc.
Even Web of Shadows got too repetitive for my tastes...
I dunno how else to explain it but when you compare a game like Arkham, for example, to recent Spidey games, you can just tell the difference between one and the other when it comes to the gameplay. I never tired of playing Arkham City...so much fun, I played the game from start to finish several times without ever getting bored. Can't say that for any recent Spidey games. Spider-Man 2 and even 3 to a degree were the last Spider-Man games I played that avoided the repetition curse.