Honestly.. intervention is annoying even in Victoria.
It is realistic in Victoria, because it allows the great powers to turn around and say, "oh, it looks like you're trying to become a great power through military expansion.. hahaha.. no" and contributes to the overall weight of inertia which Victoria tends to build up over the course of a single play through. The Victorian era wouldn't be the Victorian era if the powerful weren't getting more powerful and everyone else wasn't getting their faces stamped on. It works in that game, but it is (I suspect) a big part of why Victoria is the nichest Paradox title. Most players don't like having success or failure be entirely at the whim of a capricious AI.
The other thing is, if you could simply jump into any wars you wanted, what would the point of alliances? Alliances in Stellaris seem to entail considerably more of a sacrifice than alliances in any other Paradox game I'm aware of, because you are effectively giving up a degree of control over when you can and can't go to war. Why would you ever do that if you could just intervene.
One thing I noticed a lot in the stream chat at that point was people talking about "space condottiere" (or "space expeditionary forces", I guess, if you're using HOI slang) which seems like a much better idea in terms of giving people the ability to influence wars they aren't part of, to me, than intervention.