I would say that it depends on the warrior as to whether or not they want to be in a front line unit that regularly sees combat.
For example - young go getters that want to make a mark will be looking out for units (be it front line or garrison units) that see combat regularly so that they can gain skills and get noticed and maybe climb a rung or two on the rank structure. Middle of the road warriors who have seen a few knockdown battles and maybe have been assigned to a front line Galaxy, maybe a Star Commander or Captain might want to see less combat and more stability to make sure they protect what they have gained over the years. Warriors that have been in uniform for a few more years will know that they aren't as fast or active as they were and want to sit on a cushy assignment somewhere in the middle of nowhere where things are quiet and no one wants to shake the tree overmuch even if it is a 2nd line unit.
I would say that a Keshik is where you go when you are top of the league and trusted to be a solid, solid team player and you can maybe look for some stability and not have the constant hassle of trials every month. Maybe transfer out in a while to a command rank somewhere comfy with the favours from people you know and the prestige of being in a Keshik so you can maybe bring some of the warriors under you to a better standard than they could be.
Some Keshiks might be like that. The Ghost Bear Loremaster Laurie Tseng had a Keshik full of her lifelong friends. In that Keshik and under that specific leader particularly I can see what you describe.
But others, like the Turkina Keshik in the 3050s, (FM: CC), are specifically noted as a top assignment, whose members routinely go on to command their own Clusters and Galaxies. Also, even though they see less active combat, their combat record is considered to be unparalleled within the Clan. As a kind of poster unit for the Clan they also always stick to Zell and contain no freeborns. So the Turkina Keshik reads like a highly elite poster-child unit that is also a political and leadership proving ground for the best-of-the-best before they move up and out to the next phase of their careers. It doesn't sound cushy at all, it sounds cutthroat and ambitious.
Each Keshik really is different, you can read the fluff of two different ones, and walk away with completely different takeaways. It really is remarkable how differently the Keshik concept gets applied with each individual Keshik you read about. The motivations for joining one is equally varied.
If I'm a Bear warrior looking to join Laurie Tseng's Keshik, I may very well be the kind of warrior who is looking for a calmer, steadier existence among some potential lifelong trothkin.
If I'm a Jade Falcon warrior, I want in to the Turkina Keshik because I'm ambitious as heck, and I want that next rung up the ladder, and I want to gain the attention of the Clan leadership, and become one of the Clan "insiders" and join that super exclusive club of the warriors earmarked for greater things.
