Something I get from making my mini battalions, which is probably closer to the real world, but which doesn't feature in 'pure' board or megamek games: transport.
Yes, BA are tougher than infantry, and move faster, but they're strategically as slow. Between battery pack life, operator endurance (do you really think most BA can jump continuously for hours without getting worn out?), and the paucity of all-omni units in most IS armies, all the problems of getting BA into contact on a game map are magnified when trying to move them in the real world.
Then there's the lack of dedicated BA movers until more or less late Jihad. Yes, you've got the Karnov ... but while you can move a typical company of leg infantry in two Heavy APCs, a BA squad demands its own carrier. And anything that had 3 tons to carry an infantry platoon need not apply.
Now when making my units, for the sake of economy, I cheat. I think it's fair to say that quad BA don't need their own transports, unless (like the Sloth) they're massively slow. I can see a Fenrir, with the operator sitting in a chair, bounding long for hours. And I can also see 'ordinary' units having mixes of infantry & BA in their support units. But if you want all BA, all the time, you have to take all the transports.
Which, in logistical terms, adds size, complexity, and numbers. Convoys of hover APCs are great in terms of getting those BA to the strategic objective before the 'other guy', but need to be escorted lest they be taken as a target of opportunity. More so with VTOL-deployed BA.
And when faced with the choice - "Sir, we've met BA production targets for the quarter. Both the APC and 'Mech lines are demanding priority. Who gets the extra cash?", I'm guessing we all know which way an IS general is likely to choose.
W.