Obviously, I don't know how efficient the SC code is. But how difficult could it be to expand the map? Add another couple of HQ levels? Add a second hero. Put walls/fences in to make the defence better? TF wars. Man it's endless. If I'm paying you $120 a year, and you have hundreds-of-thousands of players like me... it's got to be worth you hiring two devs at $75k each to just keep adding to the game? You could even add in a $40k QA guy.
Think through what you said. What does a new HQ do for the game? It just adds another grind for maxed players and extends max for non-maxed players. Balance would be maintained so at the end of the grind... you are right where you started. Another HQ is really just busy work IMO.
What does expanding the map do? Spawn rates would not change. It could provide some more reserved vp for LB Cloud openers. But what does map expansion do for the game?
A new hero, might be interesting, but how does that reinvigorate the game?
Walls and fences might shake up game play a bit so might be invigorating.
I think that Live PvP May be able to set the ground work for Live TF wars. Would probably strongly invigorate the game... at least for a while.
Now... software developers are not making $75,000/year. I was a software engineer. I am now a technology executive in a world wide company with a very large staff reporting through me. I am extremely familiar with IT salaries as a result. A decent developer in an average market can pull $110,00/year. A great developer can pull $160,000+/year. Add workspace, equipment, tech assets, benefits, bonus and retirement on top of that too. Also adding resources to a technology project team does not provide a linear increase in development capacity. If you are interested read “The Mythical Man Month”. If the B.B. codebase has a large amount of technical debt, two developers might not be enough to do much of anything.