Consider this as you frenzy over these concepts: the original introductory ruleset was written to a specific sort of balance, and Clantech, while it did disrupt that, didn't overturn the basic concepts quite so much.
Now, you're talking changing the basic dynamics of the game itself, as a core rule.
so you need to ask yourself: "What is my endgame objective?"
How do you want the game to play?
lemme give you an example of what I'm talking about...
3005-3025: the Introtech era. We have ballistic weapons, we have energy weapons, we have a situation where only one energy weapon (the PPC) and one ballistic weapon (the AC-20) are capable of nailing a cockpit and destroying the head it's mounted on, we've got a mix of missile, ballistic, and energy weapons that isn't uniform in the canon designs, because the setting involves a sort of "game of thrones mixed with Mad Max" feeling, a REAL 'Dark ages" complete with analogues for the various European royal families and the pre-Reformation catholic church. It's "Rome has fallen and we're scrabbling for the scraps".
3035-3049: The Helm Core era/recovered tech/we've got a dominant empire era. WE start seeing ballistics doing cluster damage, a few minor improvements to armor and other systems, extended range energy weapons (Congratulations, you've reached the equivalent of the 15th Century's early renaissance!).
3050-3067: Clantech era. technologies take a massive jump, but follow the same patterns, only with less weight, or more range, or more damage, or some combination thereof. everyone is still copying everyone else's advances. (See: Heavy Machine Gun, "Light" machine gun having the same stats whether Clanner or Inner Sphere, only the weights are different.)
3068-31xx; Maxtech Rulez, nothing munchkin that was ever published is excluded, and some of the rules added only make sense mathematically. even here, there was some attempt at balancing, but we're a long way from 3005's fairly narrow set of rules and equipment. The point where the weapons lists and special rules require additional volumes is well past, and you can't both generate a custom unit, and run a game out of the same 300 page book.
instead, it takes seven volumes and you're going to spend a LOT of time looking things up.
which is great for book sales, but maybe not so great for bringing in newer players, which is why the quickstart rules had to be created.
So...
you're talking about a massive jump in timeline, and a change to the tech-base...
what's your objective? How do you want this game you're designing to actually PLAY? how many new products are you going to need to play it? How compatible w/ previous versions of the game are you comfortable with?
who's your audience, and how will it work with increasing that audience?
alright, business rant over.
Here's a few of MY suggestions:
1. Faction specific developments to solve different problems. This is like a reaction to the HMG/LMG stat thing, but it applies to a range of ideas...
a) variant solutions that aren't so much raw better/worse than different approaches to the same problem. a "Heavy" mg that does 2D6 to infantry and ranges out to 6 hexes for 2 points of armor damage-but, does 3 per shot internal explosion when the ammo bin is critted, for the same .5 tons/weapon as a Clanner HMG that does 30% more damage at 1/3 the range.
b)MMLs as standard missile launchers with selectible (by tonnage lot) ammo, without integral Artemis because sometimes, it's not worth equipping.
c)Improved version Infernoes for vehicle killing. how it works: one hit, forces a survival roll, vehicle makes the roll, they need to un-ass from the location or die next turn. Roll is a piloting difficulty base 8. (basically, the OLD inferno rules). Kills 3D6 infantry or 1 BA trooper per turn spent in the zone, fire zone lasts 1D6 turns, clears heavy woods in a single shot, (SRM only). This basically goes back to the 'old' inferno rules, and makes pillboxing your tank a losing proposition unless...
d)Fire suppression systems: requires 10% of your vehicle tonnage, for Battlesuits a fire suppression system weighs 100 Kilos. Completely negates all fire damage including inferno for up to 3 turns, has an 'ammo' stat giving 2 charges per BA suit, or tonnage divided by 5 charges per vehicle.
e) Chaff/jammer dispensers for aircraft. clutters incoming fire, adds plus Three to the attacker's difficulty, limited to half-tonnage lots on aSF andVTOL units, ammo based with 5 shots/ton devoted. May be carried as external stores.
f) VTOL air-droppable probes/sensor dispensers. sold in 1/4 ton lots like Clan MGs, delivers 5 localized probes that negate ECM, Camouflage and Stealth systems in the seven hexes they cover. May be destroyed by infantry on a successful short range attack roll.