I also soak my harmonicas when they get hard to sound--and I use wooden ones. There are some who say that when you soak the wood ones before each session you make the wood swell and so make a better air seal.
One point about the chromatic harmonica. It is pretty much a melody instrument. That is it is difficult to play chords on it. Also the standard tuning of a 10 hole diatonic (like the marine band etc) is designed so that if you do happen to sound two adjacent notes, you have minimal chance of getting a disonance. With a chromatic, you usually get a real clunker of a sound if you hit two adjacent notes.
There are some intermediate harmonicas which are not chromatic, but which have sharps in place of some of the duplicated notes on the standard (so-called Richter) tuned harp. One is the Hohner Country Tuned, and another is (I think) the Lee Oskar Melody Maker. They make it easier to play melodies, but you have more danger of producing a bad interval if you hit two adjacent holes.