I'm a huge fan of the idea of making mercenaries permanent in some fashion, but I haven't had an idea that absolutely grabs me just yet. Here are some random thoughts relating to them that kind of get at where my head is at:
1. Overall I'm wanting mercs to be something that are just a part of the game, but if they're something that cost a bunch of hacking points or anything else irreplaceable, then a lot of people just will never capture them because "friends that I can't control" are naturally going to be seen as a wildcard. Plus if the mercs don't do exactly the right thing and you paid a ton for them, people will be understandably upset.
2. I'm also reluctant to have too many steps for using mercenaries. Right now having to go capture them or do whatever with beacons actually kind of bugs me, because I feel like that delays when I can use the mercenaries in general, and it makes them just feel like any other thing that you capture (and there's plenty of that already, plus more coming). To some extent I kind of want these to just show up for your use like the "home city" cards in Age of Empires 3. Not exactly like that, but that sort of "I'm just playing and now I have a bonus I can whip out if I want" vibe.
3. Having mercenaries be something that have a bit more impact is good, but also something that isn't gone forever once you use them.
3.a. Those are a bit at odds with one another, so it's a tricky balancing thing. If the mercs can't be gotten back easily, then I'll always just save them "for later" forever, rather like elixers or other rare items in early Final Fantasy games (FF6, etc). There's never a time where you feel like things are going so poorly that you definitely want to use the mercs if they don't recharge.
3.b. But if these mercs are super powerful, then when you're about to lose it's just a matter of summoning ALL the mercs at once, and probably you solve the death you were about to have. And if those are rechargeable too easily, then that's wicked unbalanced and you just have these things all the time coming in and solving all your problems (or choosing to do the wrong thing, to your frustration).
3.c. If the mercs are too powerful or too expensive (too rare), then the perceived opportunity cost of summoning them at any given time is scary high and people will still avoid them.
4. To some extent, a "use it or lose it" system is often a solution to this sort of hoarding behavior, because for instance if we had:
- "mercenary summon tokens"
- and you could only have something like 5 at once
- and you automatically get more tokens as you do something-or-other
- then whenever you're near 5 you're going to want to spend them to bring out the mercs even if it's not dire just so you keep having more.
- this basically prevents stockpiling, versus giving a time penalty for not using them -- so inverting the "lose it" aspect. More of a "don't gain more of it" thing instead.
5. If all of the mercenaries were available from the start, or even better if mercenary beacons were "activated" as soon as they were scouted, then you'd suddenly have these other forces you could do something with that wouldn't be something you have to go think about.
6. If mercs didn't cost metal (which isn't that interesting in this context), but you got something like "mercenary credits" every time you did certain activities, then we could actually make it so that every time you were about to get more than the max mercenary credits (aka you have 5 credits and that's the max and you just get one more) that it spends to summon a random merc group you know right away rather than wasting the credit. That wouldn't affect the rest of your economy, and would kind of auto-teach players that mercenaries are even a thing, as well as reminding them to use them if they want them handled as ideally as possible. That way you don't actually lose anything when you would be hitting the cap, but instead you wind up with mercenaries just showing up with a little note about why.
7. How would we get mercenary credits? I think it needs to be something that you're automatically doing, or several things you're automatically doing, so that it's pretty automated. I guess one way would just be an automated timer, as the simplest thing. For every 15 minutes of gametime you get a credit, for instance. That could encourage some bad behavior, though. Instead it could be that you get 1 credit every time the AIP rises at all, which would cover a whole bunch of cases. Whether the event causes it to go up by 1 or 10 or 100, it means another merc credit, which would actually encourage people to sometimes seek out the low-AIP increases in order to get merc credits if they're running low.
8. In general if something is making it complicated for me to use the mercs, or it's expensive to get them or use them (in terms of my time or attention or literal metal or science or hacking), then I think they'll always lose out and be underused because we all prefer units that we can actually control ourselves. But having friends that we can direct in a small way (summon to X location) are definitely a plus.
So... yeah, lots of random thoughts.