I wouldn't say that it "needs to be fixed" so much as "I'd really like for them to work on it". That's not a dodge, but rather a nod to reality. There are a crapload of clans searching for war at any given time, at 10v10 up to 50v50, and for most of them, most of the time, the MM does a pretty good job. It does especially well with mostly-balanced clans that have a reasonably tight th spread. It does especially poorly with clans with a very wide spread from top to bottom, and if you throw in a bunch of .5's into that mix on top of it, especially .5's that that have the troops to 3* low 10's and 2* max 11's, then it's just going to be tough to find a comparable clan to match up with in many cases. Additionally, you probably have gotten used to longer searches, but if you let the search run over more than 30-40 minutes then the search parameters get relaxed even further, which can often greatly increase your chance for a mismatch.
To be honest, I don't know that the devs are going to get the war mm search parameters "fixed" a whole lot better than they are, but I do think that they're good enough for now. And by that I mean that they're predictable enough that those who want to aim for balanced wars can pretty much always get them, those who aim for imbalanced wars can pretty much always get them, and those who just throw a group together to make a war party are more likely than not to get a reasonable matchup.
fyi: Max th11's just further skew your war lineup, but the example that I listed above still holds. If I were you then I would throw everybody into every war, but strongly encourage your 9.5's to slap down their infernos and put their bases in order. If they're good enough to 3* early 10's and regularly 2* 11's then you'll see a big drop in unfair wars, and you probably won't run into any more opponents with greater skill; ie, you'll get more "winnable" wars, and the boost to morale from knowing up front that you're going to have a fair and competitive war is hard to overstate.
We have already developed a work around solution, so tbh I don't care if they "fix" the mm or not. I know that as long as I upgrade my bases in a mostly common sense manner and don't put together unbalanced war rosters then I'll get reasonable war matchups, and if I hone my attacking skills and my clanmates do the same that we'll win a high % of those wars and have a lot of fun doing it.
Isn't that enough? You talked about having a bunch of .5's in your clan, that's engineering. My clan was like that for a long time, so I'm not being judgmental about it or anything, but the war mm is much more harsh on .5's these days. Or, perhaps to put it another way, the war mm is much quicker to classify a clan as imbalanced today than it was previously, and I have zero problem with that at all. My clan recognized that early on and started throwing down infernos and xbows like crazy to even us out. If your clan evens out its roster and has a few max 11's, a cluster of 10's with infernos, and a bunch of full 9's, then you'll probably match up pretty well with a lot of balanced clans. Heck, that sort of roster is what you see in CWL, right?

