Zero, the reasons that people keep saying no to your idea is because mechs are too vulnerable, large and heavy, complex, expensive, and above all REDUNDANT. i will review these points one by one.
1. vulnerability-mechs will not have heavier armor than tanks. the reason is because of the joints. the joints can only hold so much weight. you can't armor said joints or else they can't move. take out the leg joints, and the mech WILL fall. you can't say "well, mechs will have heavier armor then tanks." No they will not. tanks will use this special armor of yours before mechs will. also, they can't put more armor on because it would screw up the balance.
2.Size/weight-hitting your mech is literally like hitting a barn door. it is too tall to be concealed effectively, and has very large blind spots. as for weight, tanks are already heavy enough, but your proposed mech would be even heavier. so heavy that they will sink into the mud, or crush roadways. tanks don't sink into the mud or crush roads because of their tracks. these tracks are very large in terms of surface area, thus distributing that weight. look at it this way, when you walk through snow with snowshoes (the tank treads) you don't sink. when you take off the shoes like the mech, you would sink.
3.complexity-for this explanation, i will look at an actual time in history, WW2. The Allies (in this example, allies refers to US,UK basically) used the M4 sherman tank, while the Germans used the Tiger tank. The Tiger was a much more powerful tank, but was extremely complex. the Sherman was very reliable, and was built in HUGE numbers. Because of the Tigers complexity, very few were built. so in a 1 on 1 fight, the Tiger would win. it was rarely one-on-one though. most of the time it was 4-on-one. as a result, the Tiger might take out 3 of the 4 tanks, but all it takes is one shell from behind, and POW! no more big-bad tiger.
4.cost-In addition to the price of building ONE mech, you also pay for R&D for the mech, R&D for the weapons, building the weapons, building the equipment needed to build the mech and weapons, delivering the weapons, AMMO, training the crew, ect.
5.redundancy-honestly, what point is there to have a mech that can do everything? as Dauth said, "Jack of all trades, master of none." also, the tank already is GOOD ENOUGH. I have the same opinion about the F-22, but that's another thread.
in conclusion, the military WILL NOT spend all this money on improving an already good weapon. (hopefully)
also, how do you know that tanks won't be using batteries in the future?
edit-correction
edit2-Ninja'd for grammar and spelling
Edited by Viper, 15 September 2008 - 00:17.