The modules are based and rewarded around the suits abilities, yes.
The visor is for tactical mode: http://www.gamesas.com/gallery/screenshot/nanosuit_20_enhanced_visor
Proximity if for armour mode: http://www.gamesas.com/gallery/screenshot/nanosuit_20_proximity_alarm
So yes, modules will be unlocked depending on your play style, what modes you mainly use, etc. I believe Nathan clarified this in an interview quite a while back

That being said, the majority of modules (and how the tiers will effect them) have not yet been revealed, so i'm sure in due time there will be plenty more information available on them to discuss.
Hopefully when more information is released it will help to differentiate the module system from the CoD perk system, since from what we have seen and heard so far, the system itself is exactly the same and the upgrades have a huge similarity... Same with the "skill - streak" system in Crysis 2 (comparing to CoD Kill - Streak), but that is for a different thread.