Oddly enough, there has been criticism in the past where Labyrinth Lord called itself the Rosetta Stone of Old School Fantasy. Truth be told, it is the platform that created Original Edition and Advanced Edition. It also spawned Mutant Future and Humanspace Empires. All that's left is Alternity and Boot Hill and we got the whole shooting match. (Maybe if you're a completist, you'll want the Amazing Engine, too.)
But Swords&Wizardry has generated its own progeny as well. There's Ruins & Ronins, Ultima, and Battlemech (can't find the link). This isn't even mentioning the number of versions of the core rules and Brave Halfling's new rules in development.
Are there more clones that operate like platforms? Looking at other old school games, S&W and LL appear to be the two largest platforms. Microlite20 is a strong third, there are so many add-ons for it, that compiling them all generates a 600+ page document. Openquest is a great rules system, but no one that I know of is working on a space-based game with OQ as the foundation. The D6 game spawned all sorts of games in West End Games' hey day, but only one publisher is actively building on it. Both of these systems could be great for making all sorts of games. That's why I use part of the spell building system in D6 Fantasy and a variation of the OQ skill system in Andras.
So, what does this prove except the fact that I can add a boatload of links to a post? There a platform out there for whatever game you want to make and it is broader than the legacy of TSR.
Did you know that the STRength scale in the Action! System is setup so that the STR of a horse will scale to units of horsepower? Give a STR value to a vehicle and you have the power rating for its engine. It also scales in powers of 10 so that you don't have to have a space craft with a STR 4200.
But I digress.
I don't believe that Andras will become the platform for gamers everywhere. What I do know is that I like a game that can help me define just about anything I want. Mechs? Sure. Interdimensional Self-Replicating Bismuth Golems? You betcha. Greyhawk? Not a problem. A Spelljammer version of Tekumel? Yes, but the rest of the internet will hate you for it.
I hope that with the fair number of systems presented, folks can find something to use for their game. Skill-based wizard? Roll d20+d10 under the INT score for a rules-lite game and a roll under Spell skill for a more nuanced approach. Spell Creation System? Here's a short version and a detailed version complete with an expandable table assigning effects to point values. Vancian Spell Name Generator? How about Hastra's Delicate Surfeit. Monster Builder? Here's some tables and an XP Chart.
More than that, I also want to provide spreadsheets. If someone wants to make their own spreadsheet based generators, lots of useful data will already exist in spreadsheet format. Better yet, convert the files into csv and build database apps. Go for it. I am intentionally building the various spell lists in a spreadsheet for this reason. Monsters will exist in a spreadsheet as well as the class builder. It's one thing to provide a text version of the rules, it's another to provide a dataset for folks to build with.
The ideal system for me would be 48 pages of rules and another408 of magic item tables, classes, spell lists, price lists, etc. The GM's guide would have a bunch of tools to make just about anything from a monster to a class to a demi-plane and everything in-between. A person could basically ditch everything after page 48 and use the GM guide to recreate anything needed.
Work continues very slowly in October - with birthdays, anniversaries and non-profit events, it's a very busy time. But I have the XP tables for monsters ready as well as the SRD versions of spells in the 2e PHB in a spreadsheet. This winter, I hope to get quite a bit of work done and have a playtest document before March.
Thanks for the six people that indulged me a bit of commentary.