Before I begin, I should note that my primary "on-ramp" into the setting has been through sourcebooks and fiction. While I do have PDFs of various rulebooks for both Total Warfare and Alpha Strike, those are still the primary means by which I connect with BattleTech overall. So I'm cautious about getting too far into the finer details of how things are for on-table tabletop play.
That said, I did have a few thoughts, such as they are:
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Firstly, if the Total Warfare title is to go away, I might ask for there to be some other means to distinguish the "Classic" game system from BattleTech as an overall setting.
To put it another way: the old "Classic BattleTech" title was coined in the days of MechWarrior: Dark Age/Age of Destruction, at a time when the latter was the place where the timeline was being moved forward, and where new 'Mech designs (such as the Ares and Savage Wolf) were being created to fight in that new era. But even after MW:DA/AoD went away, it didn't take long for the "Quick-Strike" side-rules to evolve into Alpha Strike - which, as noted above, has been around for quite some time now.
And with BattleTech Universe being a "system-agnostic" way of bringing players old and new up to speed with the setting through to 3150, it would soon be possible to leverage that book for people who play what we currently refer to as TW, those more into AS, and/or for those who focus on the novels and sourcebooks as "their" BattleTech.
So, perhaps calling the new core TW-scale book... "BattleTech: Classic" (or some such) could be a way to give both it and Alpha Strike their respective due, while framing them as equally part of the present and future of the BattleTech franchise overall.
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Secondly, while the rules needed to play Alpha Strike are mostly in the Commander's Edition - minus those rules still only to be found in the old Alpha Strike Companion - the Total Warfare scale of play is of course a very different beast indeed.
Yet I was wondering about how the existence of BattleTech Universe might allow for a more flexible approach towards what needs to be covered in a "core" rulebook, and what does not.
To put it another way: perhaps it might be possible to offer a "master" or "reference" version of the ruleset, which focused exclusively on a fairly comprehensive set of rules needed for ground combat (and for aerospace ground support, so as not to leave the Outworlds Alliance and/or their current Clan Snow Raven co-tenants out of the loop). This could be in parallel to offering a more iterative set of books and box sets, in which various concepts and technologies (and background material) could be digested over time.
Indeed, one could use such a thing to encourage players to side-step from AS, should they wish to do so. As in: say if someone buys the Alpha Strike Boxed Set, and then gets both the Commander's Edition rulebook and the forthcoming BattleTech Universe book. Since the player already has a set of Spheroid and Clan miniatures to place on the tabletop, plus a sourcebook helping them understand who might use which ones in which places and points of time, a "master" book - plus a pre-curated set of Record Sheets, themed to match the AS Boxed Set, perhaps? - might be a good way to leverage what this payer already has, in order to get into a new scale of play without too much trouble.
Plus, for older players who are returning to the setting, yet who might have not heard about the onset of Alpha Strike: the above approach could be looked at in reverse, sort of. As in, they could be advised to get a would-be "master" rulebook in order to start playing "Classic" scale once again; get the Alpha Strike Boxed Set for a handy set of minis to paint up and use (and, maybe, to encourage them to give AS itself a try); and grab BattleTech Universe so as to get caught up with what's been going on in-universe while they were away.
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In this, my main point if comparison would be with the Star Fleet Universe.
Once again, a disclaimer: I don't speak for the folks over at ADB, but I have had a few things published by them here and there. So what I'm about to type is my own perspective alone.
There was a time when, in game terms, Star Fleet Battles and the Star Fleet Universe were essentially synonymous, at least in game terms. But these days, SFB is part of a broad stable of games, all set in the SFU. There are "sibling" tactical starship combat games like Federation Commander and A Call to Arms: Star Fleet (the latter using a modified version of a game system created by Mongoose Publishing); the strategic-level game Federation and Empire; the Prime Directive RPG (which nowadays uses third-party game engines, such as GURPS 4th Edition); the Star Fleet Marines ground combat game; and others.
Of course, SFB remains at the heart of the SFU. But the Venn diagram of players interested in one or more of these game systems would not exactly overlap. Indeed, there are some games which suit the use of miniatures (to include the vast range of minis ADB now offers via Shapeways) over others; for example, ACtA:SF is both hexless and entirely miniatures-based, whereas both SFB and FC are hex-based and primarily (though by no means exclusively) designed around the use of counters.
But with of both SFB and FC, there are different ways to get into either game system, along the lines I noted above.
In the case of SFB, one option is to buy the Basic Set, move onto Advanced Missions, and then go from there to wherever in the game setting you might want to go (to the Early Years, to alternate settings like Omega or the LMC, or elsewhere and elsewhen). Another option is to buy the Master Rulebook, which includes the rules needed to fly a given Alpha Octant starship; a Master Starship Book for your chosen Alpha empire (Fed, Klingon, etc.) to get the "R-section" data needed to explain the ships being used; and then order this or that SSD book as a spare part or PDF to make use of in actual game play.
Similarly, FC can start with either the Klingon Border or Romulan Border box sets, and then build out from there. But it also has a Reference Rulebook which consolidates most of the rules needed to use the various Ship Cards, which in turn can be ordered as spare parts or as PDFs.
So, if someone wanted to play both SFB and FC, they could mix and match the means by which they can get the tools they need to play both games. Or, if thywant to stick with one or the other, each offers multiple "on-ramps" to get them where they might wish to go.
Given that the SFU and BT are both long-standing game universes with their own respective families of game systems to build upon, it seemed... logical for me to keep both in mind in conversations like this. But, of course, parsec-ages might vary on that front, so whether anyone else agrees or not is another matter entirely.