No no, the point is not to add MORE tugs but to revise the existing ones.
I am late to this discussion, but this line caught my eye. We (at least some of us) do not want more tug types.
As of now there are way too many tugs. In the beginning I thought, hey cool man, what a nice lot of small auxiliary ships. Now I have stopped building anything else than 66% fleet and 66% starship tugs. Only when my fleet goes beyond a certain size do I build 33% tugs. And I never build 100% tugs, I simply do not understand the concept of repairing a ship that isn't broken. Pulling out and repairing a ship that has got 1% damage is imo an enormous waste of firepower. And the engine-repair tugs: Most of the time they just sit and do nothing, and when you really need them, they have all been killed by the last Ion Cannon you encountered. Rather than remembering all the time to check if I have still got all my six-seven-eight different types of tugs I prefer to just manually repair all ships with engine damage by help of my (ever-present) engineer squads. This is too much microing, some would say, but it is not as ridiculous as constantly checking if you still have got all those many different tug types.
The last few games I have actually stopped using tugs at all, instead I am bringing two-three MRSs along with the main fleet: One is right behind the fleet, the others are ready for fast deployment when the first one gets killed. Note: This is not to my liking, I really do like the tugs, the problem is that there are too many types.
Like the suggestion with an engine-repair-only engineer type, I don't like it. This might lead to a host of different engineer types, just like the tugs. Just inventing a new specialized ship type every time you feel the need will get us all bogged down in hordes of different auxiliary forces. Totally unneeded complexity imo.
The constructive part of this post: I believe the way to go is to stipulate engine failure as some sort of major damage, equivalent to perhaps 75% 'conventional' damage, so that all repair tugs will grab a ship with engine damage. Just like the engineers now are all-purpose units.
In my favourite design there is
one type of engineers (like now, with three tiers), and only
two basic types of tugs: a fleet repair line (two flavours: 66/33), and a starship repair line (same two flavours).