I really love "Mystery of the Blues". To be honest, I wish they did make a snow-themed Indy movie as Indy 4 instead and had made KOTCS Indy 5.
Looking back, the biggest flaw of KOTCS wasn't anything about the movie itself, but rather the fact they waited too long. A lot of missed opportunities through the 90's-early 00's. They can obviously still do Indy 5, but you can't deny Ford is getting up there in age.
A damn shame they didn't make Indy movies more often and make Indy more Bond-like in the sense he's well-known to every generation and wasn't considered just a piece of 1980's nostalgia.