Yes, I can see this issue. My thought to preserve balance was to only make this additional ammunition available to a Demolitions Master, and to increase the skill costs accordingly in alignment with the significantly increased utility. Also, it would be possible to make the ammunition sufficiently weak and/or scarce so as to preserve balance while still adding choice and interest to the game.The problem with adding more explosives to the game is that they are an extremely useful multi-purpose tool. Blow open locked doors, blow up cameras, turrets, alarm units, robots & NPCs, they have the capability to blow up multiple targets also. Too many explosives will throw the RPG systems/general game balance off.
I would imagine that exploiting all the various uses of explosives that you mention would be precisely what a demolition expert would do to get through Deus Ex. However, I would also imagine that the strategy of blasting one's way through the game would likely have some significant natural drawbacks as well - for example a total lack of stealth.
Side note... I have always found it odd that setting off explosions in Deus Ex seems to so frequently go unnoticed by NPCs and this has, for me at least, a tendency to break immersion. It seems like there should be much more of a stealth penalty for, say, blowing open a door with a LAM or the GEP gun. For example, an automatic alarm and/or AI investigating the source of the noise.