First expendables was dumb fun insane action, minus Mickey Rourke trying to bring "substance". There never should've been a sequel though.
I actually thought the first one was the worst. The acting was really bad in some scenes and I don't even remember the villain or the plot.
The second one had better action and a better villain...still, I thought it was boring until the final battle with all the actors. It was dumb, but more memorable than the first film. Plus watching Sly, Willis, Arnie, and Norris fighting together was kind of cool.
My favorite of the three films was the last movie. I thought the third act action was pretty good and over the top fun, but I only saw it once, so my opinion could change. I also remember liking Mel Gibson's character. Overall, it's Stallone's weakest franchise, imo. Still, I give Stallone credit for getting all those actors in one trilogy that pays homage to 80's and 90's action films.
I wish Sly and Arnold would have made a film together in their prime. They could have made a team film with the two of them fighting together Contra style against aliens or terrorist...or something. Or they could have made a VS film, with both guys fighting each other. Instead Stallone made Tango and Cash and Assassins instead