After playing D&D for 15 years without maps and figs, I think that using figs is a huge improvement. Without them, combat usually consists of something like this:
Player: I swing. 22. I hit. 12 points of damage.
DM: Ok the orc swings. 12. He misses.
P: Ok, I swing. 19. I hit for 10 more. Is he dead? Good. I move to the next orc.
It becomes very repetitive. Of course the DM can embellish it with descriptives, but the combat soon becomes completely reliant on the DM. Only the DM can really say when a character can use certain feats, where spells are best placed, and so forth. This is essentially cutting both the options available to the characters and the interactions open to the players in half. Plus combat becomes basically arbitrary or random, i.e. based on DM decision.
DM: You managed to catch only two ogres in the fireball.
or
Player: I dropped my orc. Is there an orc near enough to me for me to use cleave?
DM: Umm. I guess so. Yeah.
Now you can argue that some people might find this style of play more fun, but it seems much less fun to me. The game has becomes infinitely more intricate and non-repetitive, as characters manuever to avoid AoOs, to take advantage of reach, choose to tumble, take 5 foot steps, cleave, etc. There is alot of variation before battle starts repeating. Plus, this is the best of both worlds: there is lots of strategy and tactics, but nothing is stopping the DM from giving rich descriptions of the results that the players' independent maneuvers resulted in.
Minis and maps forever!