This, for the record, is an OC opinion - IC I do what Mandalor says / what comes naturally.
I would like to be able to have interactions with other factions beyond raiding them, or invading them, personally. So perhaps if we extend the discussion beyond 'best buddies on a leash' allies to 'not shooting or raiding at each other right now' allies? Yes, raiding and combat is like... 70% of being Mando, but there can be the remaining 30% or whatever.
I'd like to be able to legitimately hire out to help out a faction in return for resources, without a blanket 'no, you're not trusted' from the actions of the ME as a whole. Which is the prevailing opinion at the moment, and will only harden if our only allies are the TSE, as cool people as they are. Heck, there's no reason why we can't all out hire out - if we're not expansionist, we've got spare invasion slots for sale, and writers who want to blow things up.
I think we've got a good thing going with the 'standing alone' thing - but a bad thing going with the 'can't be trusted with string' thing, and there is a middle ground we should aim for - the factions I listed above are mostly my OC 'I don't think these people would cause us OC or IC pain' list.
The point about not being leashed to be nice is a good point - I don't think we want that, but I don't think restricting out alliances to the dark factions is the way to go there - they can be just as restrictive. We should be free to pursue the goals we need/want from a story perspective (and I am aware there is on-going story with the TSE alliance, which is why I put them as thumbs up, story should play out).