What do you find disappointing about it? Imo it's up there as among the best combat in the genre. The fluidity, polish, level of freedom and dynamism is pretty much unmatched. It combines raw action, stealth, melee and platforming together in combat, better than any other shooter, and the animations, cover system and aiming are also all top notch. The way you can just easily jump, climb or swing about, to constantly gain advantage, flank, get in to stealth etc, completely effortlessly and with immediacy, can be truly liberating. The incredible level design and quality AI also help encounters.
Granted not all of the combat segments allow for full combat gameplay diversity, but several certainly do.