An excellent point.
Army A:
9units
Army B:
1u 1u 1u
1u 1u 1u
1u 1u 1u
Which army represents more troops? Neither.
Which is more strategically valuable? Indeterminate considering all the possible variables of war, so arguments could be made for either side.
Solution? The argument has to take a step away from realism and focus on game mechanics, which the developers are addressing and handling it the way feel will provide the most fun and most balanced result.
It's fine to have concerns when a series is moving away from a long-term practice (or anything you're particularly used to or fond of), but considering we've only brief explanations and little in the way of physical evidence regarding how the new system works (in practice, not just in theory), I'd say it's only fair to hope they know what they're doing and that it'll work out.
I, for one, think these changes are exciting and can't wait to see the new system.