First of all, I have to make one thing perfectly clear:
I love Battletech.
No, that wasn't strong enough.
I ****** LOVE BATTLETECH!!!
Ever since a kid sitting on a bus next to me first pulled out a TRO 3025 and I asked, "What's that?" Battletech has been a huge part of my life. I'm STILL mad at myself for leaving a copy of Sword and Dagger at the O'Hare USO. I could add a hundred more anecdotes, but the point is that it was my first wargame, one of my first RPGs, and still holds a special place in my heart.
That does not mean I think it is perfect.
I've been aware of its flaws for years. Clunky, complicated rules, incompatibility with canonical battles, long and inconclusive games... I won't go on, because the moment I first played Quickstrike it stole my heart away from Battletech.
Now the only part of straight BT I enjoy are the design rules, because complication and transparency are a GOOD thing when it comes to the underpinnings of a game's units, but during the game itself it's pure death - imagine if every first-person shooter stopped for a second before every bullet to judge whether your target dodged, where the bullet hit, whether the target succumbed to shock, or if the sound of your bullet alerted all his companions? Then paused for another second for each of THEIR bullets?
While Battletech has points in its favor, Quickstrike is the superior product - like comparing a Model T to a Shelby Cobra GT350. Yes, one came before the other, but that doesn't make it better; and the second gets you to the same destination faster AND in style.
1) RULES ELEGANCE
There are three types of rules-sets: simple, complicated, and complex. Simple is not a bad thing, if the game only covers a narrow idea (Ninja delivering hot burgers while dodging security and samurai!) then it works. If you try to extend out simple rules too broadly, though, it doesn't work.
Complicated, though... some game designers are under the impression that adding new and unique rules in a new book will add more fun to the game, when it fact all it does is necessitate more tedious book-flipping and arguments. Palladium Games is the worst for this, but Battletech has always been another example. Currently there are FIVE rulebooks that stack in at 300+ pages apiece (Total Warfare, Tactical Ops, Strategic Ops, Tech Manual, and A Time of War), each of which have rules that could be applicable at any time - for example, I like AtoW's Pilot abilities, but damn my eyes if it isn't another set of books to flip through.
Compare that to Battleforce, which has everything Battletech does (Space warfare? Fire? Critical Hits? Heat?) except the design rules in less than a hundred pages of StratOps. It abstracts the rules near-perfectly; I mean, for the purposes of a tabletop wargame do you really need to know whether your hip or knee actuator got hit, or is it enough to know that you've suffered a Motive Hit and your unit is slower?
Or take heat. The abstract concept of heat is "In exchange for slowing down, making it harder to hit, and possibly shutting down, you can do more damage briefly." Is a full 30-point heat scale REALLY necessary to represent that concept? Or would it be easier to say, "this 'Mech can overheat to add extra damage, but if it adds four points total it shuts down, and for every point it has a penalty to hit until it does nothing but vent heat."
Battleforce is cleaner. It covers all the same situations. It's easier to use. It's... complex: a rules-set that has almost all the bases covered, does so easily, and is applicable to a variety of situations.
2) INCOMPATIBILITY WITH CANONICAL BATTLES
Ironically, this was the original reason for the creation of Battleforce - while Battletech is scalable up to about 6-8 units on a side during a single game session, in the canon of Battletech unit engagements are usually at the battalion level or higher. Smaller combats might take place as skirmishes, but the actual determining battles are at much higher levels. Even the scenarios laid out in the older books were always described as "after a major combat," or "ambushing an outlying unit," never "This is the moment that the Fifth Deneb Cavalry broke the back of the Eighth Sword of Light." Some battles were described as duels or heroic one-man-on-the-bridge, but those were after or during major combats with 24 or more elements on a side.
Battletech can't do that. It just can't. It breaks down at high levels.
Enter Battleforce, with its abstraction of everything to do with Battletech. Created to simulate these large battles, its first iterations were rough, but nowadays it's a smooth machine for larger battles - and works for smaller battles, too, without all the unnecessary extra rolls. Which brings me to my next point...
3) LONG AND INCONCLUSIVE GAMES
Let's all be adults here. How many times have you played Battletech games where for half of the game time you were rolling to hit, rolling to find location, rolling to find how many missiles hit, and only scratching out circles in the armor without accomplishing anything? The excitement in Battletech only starts once the armor is pierced and critical hits are rolled - that's why TACs are such a popular additional rule.
Why does Battletech have a minimum of two rolls per weapon, and a maximum of 22?
While there are workarounds like software (Megamek!) or dice boxes, it's a fundamental problem with the rules itself if they're so complicated you can't easily play without those aids.
Battleforce does away with those excess rolls, and makes it so that each and every roll you make matters, dammit. Yes, it sucks whiffing four or five times in a row, but each of those rolls mattered, unlike "Out of five medium lasers, three hit, one hit the right torso, two hit the left arm, oh, I get a critical roll? Ok, I roll... a three. I don't force a PSR, darnit."
You can pinpoint critical rolls and important missed opportunities far more easily than with Battletech, where you pound on each other for half the game before anything really happens except pure lucky headshots or TACs.
Can any other fans come up with more reasons to prefer Quickstrike to Battletech?