I can see that. There’s at least a chance of history turning out like it did, which is more realistic than no chance, and it also sounds interesting. How often does this send the Empire into a death spiral, as opposed to a strong emperor saving it?
In my mod I also put in other changes, so the effect on vanilla may be slightly different.
Anyhow, from the test games (about ten) I ran using those changes (giving weak claims on the empire to relatives of Constantine Monomachos and a few prominent generals such as Romanos Diogenes, and a strong claim for Alexios), a few observations can be made:
1. A large claimant war where the claimant is
not a Doukas has a good chance of happening, particularly after Constantine X dies. There's still a good chance the claimant war might support one of Constantine's other sons not born in the purple. (Although there was two or so test games where no claimant wars happen.)
2. The first claimant war if it does happen, will start anytime from the end of the Seljuk war to the early 1080s.
2. The claimant supported is entirely random, unfortunately, as a byproduct of the arbitrariness of the faction system. Anyhow, from memory, in one game it was Constantine Monomachos' grandnephew (who in-game is a courtier... somewhere), in another where Alexios died young it was his only son. Generally, as stated, since it's kind of random pretty much anybody with a claim could be put on the throne.
4. After a different dynasty is put on the throne, there's a good chance a Doukas will attempt to reclaim the throne in a succeeding claimant war, which can happen anywhere from a couple decades after the game starts to as late as c.1120-1130. If it's early enough, and there's still a good number of claimants running around, there might be another claimant war to put a different Doukas or a non-Doukas on the throne.
5. Ultimately, things settle by the early 1100s and the mid-1100s at worst, and by this time most of the old claimants or their heirs would have died, meaning the pool of possible claimants is again relatively smaller. Generally the "victorious" dynasty - whoever survives as Emperor until then - will likely rule the Empire for a relatively long time afterwards.
6. Due to my changes I don't know if in vanilla this would cause the Empire to collapse completely by the early or mid 1100s (it doesn't exactly in my mod, since that has other changes). Historically the Turks started running into Anatolia, and the Normans in Sicily started attacking from the west, but vanilla doesn't exactly mimic this well unless you start ~1077+.
So essentially the changes I have aren't perfect and don't do everything that one would want in terms of historical plausibility - however, they do seem to mimic at minimum the chaos in the Empire from 1066 until ~1080 (and afterwards) well enough, at least more so than the vanilla set-up.
Tl;dr: Giving claims on the Empire to a few more characters is a good way to help mimic the chaos during the 1070s and 1080s, because unfortunately right now at the 1066 there's only one claimant - Monomachos' daughter - outside the Doukas clan.
