I just wanted to add my two cents to this conversation which is one I've given a decent amount of thought to as a player of both MWO and WOT. After looking at all of the arguments I think I can somewhat summarize the feasibility of mechs in the future with mechs being better offensively and tanks being better defensively. However, these divides are purely on the grounds of military capability as I don't know much about the economics and sciences needed for these vehicles.
Summary: Offense(Mechs) vs. Defense(Tanks)
- Offense: Mechs would take the cake here. While being tall and exposing a larger target area is not as great if you are expecting an attack, their size mean that mechs have unparalleled combat flexibility. Having a big gun(or several) is no use if you can't use it and the limited vertical gun traverse and low-lying nature of tanks restricts their offensive flexibility.
EX: Reverse-slope defense: If a slope is relatively steep, infantrymen, whose human body allows them great leeway in taking cover in a variety of different terrain, can gain an advantage against vehicles, which can't conform to terrain as handily. This situation allows for an attacker's height to become a disadvantage, as they can't fire as readily, and creates a cover advantage for the defenders. mechs would have a similar advantage in this situation as they could hide below the hill line and fire on vehicles as they try to get into a downward firing position.(mechs would also dominate an offensive uphill assault as well. Mechs height and posture would allow them to fire on entrenched enemies far quicker than a tank could. A tank would have to reach the top of the hill to bring its full power to bear and would expose its a good amount of its weak armor crossing the top of the hill.)
The mobility of a mech would allow it would allow it to be used on far more worlds than just tanks. In order for tanks to be the dominant force in the far, space-faring, future, there would have to be a lot of worlds of a flatter nature to warrant the mass production of so many movement-limited vehicles. Being as mechs could operate decently on many different types of terrain, it would make sense to make mechs the primary combat vehicle of the space-faring age.
Lastly, while a mech does have more exposed area to target this also means that a mech could bring to bear more firepower, quickly and flexibly compared to its tracked counterparts. While this might not matter as much now being as most of our current weapon endeavours are still ammo based, ammo-less laser weaponry would free up room for more weapons on a vehicle. Tanks, however, would be limited by their posture/traverses/gun elevations and therefore not be able to bring as many of these weapons to bear as their mech counterparts.
Defense: Tanks take this advantage in spades. Limited firing arcs, less room for weapons and lower mobility are less of a disadvantage when you don't have to be as mobile. Not having as many components to guard and the compact nature of tanks would allow for the armor they carry to be heavier where needed and therefore much more difficult to penetrate/melt/ionize for a frontal opponent (While tanks usually do have less side and rear armor this would be negated by a defensive operation in which a tanker can reliably position his front towards an enemy at all times).
I would also like to posit an idea which would allow for many of the heavier mechs to exist. Let us assume that mechs are the dominant force in the far-future based on their superior tactical mobility. On worlds in which tanks and other heavier vehicles are not feasible, forces would need a heavier mech to counter the light/medium size mechs they face. Therefore, while an Atlas would not be very useful against a set of defenses in flat terrain, they would be exceedingly helpful in worlds where only mechs are a useable land vehicle force. Being as light/medium mechs would have a strong future based on their mobile flexibility and that therefore they would be built as a core military force, it would make sense in developing heavier mechs to deal with them. In addition, they would most likely replace tanks in their traditional assault role on these worlds with difficult terrain.
Edited by Wooster, 26 July 2013 - 04:12 PM.