I dont mind gambling on Drenthe, he is talented, even if he is a headless chicken, totally. But WHY I dont want to sign him is you put him up as an alternative as a Nedved replacement, big NO if he is the replacement. But if he is signed outside that as a squad player, then its ok. But Pavel replacements are Diego, Silva, Ribery etc.
And Gallopa is 23 and a mediocre talent. Most of those you mentionned are midtable level players or very young ones (Poli

), so they would be just squad players. But I dont see much of any room for development for Gallopa.
Guarente is similar nice mix od player that Marchisio is and is an ok squad player. D'Agostino and Cigarini would be decent because BOTH are type of players we need, even if quality may be undetermined (unsure on D'Agostino, would gamble on Ciga), both are creative registas who would make our team fluid. Poli, even if I only seen him in 5 or so games, is a very promising technical CM IMO. We should do what we can to tie him down long term, not next season perse.
All in all, small signings most of these, just squad signings, which we should only look after if we get the quality upgrades we need, and we lose Zanetti or such, and cant sign a Top CM, but need a filler player so to speak.