If those two albums are "great", then all of the others are timeless and perfect masterpieces.
But yeah, there are many good songs on those, especially Pink Bubbles. An album entirely on the level of Kids of the Century, The Chance, Someone's Crying, Mankind and Your Turn would have been stellar.
Chameleon works better if you pretend it's a collection of three solo EPs by Weikath, Kiske and Grapow. Interesting album per se, but definitively absymal Helloween album. Giants and I Believe are wonderful however.