Increase tech value slightly, so that having tech actually effects the outcome of battles. If my ships are one generation better than my enemies, that difference should be noticeable.
Reduce ship count(by increasing maintenance and lowering FL(slightly)) . This would require each ship to be more powerful, but it does two things; improves performance, and also makes each ship worth "more" and would place value on saving your fleet.
Reduce FTL time slightly(say 10%). That would mean less time to go from hot zone to hot zone, which would dis-incentivize doomstacking.
I agree with the objective but
- increasing maintenance would not make ships more valuable, for that you would need to increase build cost and time
- Reducing FTL time would IMHO opinion achieve the contrary, namely allowing a doomstack to quickly react to several sources of threat. If you want to encourage the use of several flotillas instead of a doomstack, you should increase FTL time, so that reacting to multiple threats requires splitting your main fleet.