X-Men: The Last Stand and X-Men Origins: Wolverine aren't really worthy of the universal revilement they have, often being grouped as among the worst superhero films. Neither of them are good. In fact, I think both of them are bad, but they at least have their odd redeemable feature here and there.
Besides First Class and Days of Future Past, I think The Last Stand has the best action in the franchise. The odd mutant gets a nice moment to show off their powers. That final battle, while poorly lit, did at least entertain me and I really enjoy that mutants fought off against each over using their powers which we didn't get (much of) in X-Men and X2. The subplot with Rogue I thought was also a nice addition. The Last Stand's biggest failure was there was no investing in anyone.
Can't support Magneto 'cos he's still doing the kill all humans thing.
Can't support the Humans because they're weaponising a cure for the mutant condition.
Can't support the X-Men because they're supporting the Humans.
As for Origins. It's bad. The first twenty minutes are nice, and some of the mutant fights before the climax are nice. Some little nods like seeing teenage Cyclops was cool as well. It sometimes accidentally turns into pure cheese like when Wolverine suffers a loss, and does at least try to simulate tension with a character who is invincible.
Yeah, it sucks otherwise. I only learned after I watched it that Sabertooth was in it, that's what happens when you hire a different actor and base a large part of the plot on a henchman from the first film. The detour with the old couple, Wolverine can't carry a film on his own[footnote]I think The Wolverine 2013 is OK, but by God is it hard to stay invested when it so predominantly focuses on Wolverine, regardless of how good Jackman is at acting him.[/footnote], the bullshit treatment of Wraith, the special effects are awful (the big mutant being fat, Deadpool, Emma Stone's diamond form) and many other qualities contribute to its badness, but it didn't really invoke any kind of negative reaction.