Slavic languages are simply phonetically richer than the romance languages; there's no way around it! ;D
For example, when the Poles decided to adopt the Roman alphabet they tried really hard not to add a bunch of diacritical marks to letters. They couldn't resist a few, but for the most part they indicated different consonant sounds by combinations of letters, which is why for example my surname (in the proper Polish spelling) is Bonczyk. My grandfather was forced to drop the z when he went through Ellis Island, because the immigration guard there couldn't understand what he was trying to say, so he "simplified" our name for us.
Anyway, you can have lots of diacritic variations as are found in Czech and Croatian, or you can simply expect it to be understood in context (as in Slovenian, and for the most part, Slovak) or you can end up with things like szcz, szw, ncz, etc, as you find in Polish.