Exactly.
I find the official rules, as found in TW, on how many maps to use (i. e. one map sheet per lance) lacking proper scalability. And that counts for both scalability in numbers and in technology. It's fine to use jus two mapsheets, if you want to play a fast game lance versus lance. And that is probably what most games are.
But once you go bigger, and you have to go much bigger, once you introduce Clan technology and want to use BV as a balancing system, as one star equals about eight Intro Tech 'Mechs of the same weight with regular pilots. You game jumps to 13 'Mechs, of three to four mapsheets, none of which offer enough space for proper maneuvering.
The same is true for those truly large and legendary battles of company-sized combined arms formations. A lance of 'Mechs, a lance of hovercraft or VTOLs plus a lance of tanks or a company of conventional infantry (i. e. 3-4 bases) and you look at a meager 3x2 mapsheets board. That's not gonna cut it for your hovers and VTOLs.
We once tried a battle of just under 20 units per side (company of 'Mechs plus a couple of vehicle lances) and found board a 3x3 mapsheet board was good for a really intense slugfest. One of those, where a reinforced company tries to achieve a breakthrough at a well defended point in the front, but it still leaves little enough space for hovers and VTOLs.
In a way, that's how combined arms warfare and defense in depth tend to work, i. e. there's always the next section in the front or nearby enemy position, so you cannot freely maneuver around a fortified position. But in this particular case, it makes off-board artillery or using ASF on the board very problematic. It's probably true that you should not - in the sense of realism - widen your battlefield too much, but it should be deeper in many cases.