As the singularity charges give +1 every level of charge until all power is -5 at full charge plus whatever bonus one would receive from a particular core.
I would suggest the power bonus be + 10 for a + 5 to a system to make it closer to the +7.5 that warp cores receive.
Have the singularity charge faster while cloaked, perhaps twice as fast as when not cloaked.
This would give Romulan captains time to plot their next devious move.
Make the cool down to charge the singularity 30 seconds with the 50% reduction from the T'Varo console making it 15 seconds plus whatever bonus you may receive from certain cores.
Singularity abilities should come with a 60 to 180 second cool down based on their tier.
Plasma Shockwave 60 seconds
Shield heal 90 seconds
Warp Shadows 120 seconds
Exploding Gravity Well or whatever it's called 150 seconds
Overload 180 seconds
This way we get faster charging but eliminates spamming higher powered abilities.
Make this behave more like the Shard of Possibilities for space.
Have the shadows actually move so they follow and pseudo attack your target.
The shadows should grab aggro/ targeting from any npc/player that had been targeting them.
Give the shadows 500% threat so to draw npc fire.
You should automatically cloak when engaging this ability ignoring any cool down that may have been in play.
The shadows should last for around 30 to 45 seconds.
A scenario where a target chooses to ignore the shadows and does not notice you decloak in the middle of them could fall victim and hesitate to respond quickly enough to your attack which sounds very "Romulan" indeed.
The Overload ability:
Sorry that I don't use the proper name or know how it will work but I have an idea for it.
My idea for this ability would be at max power you would receive a 5 second burst of +20 power to all subsystems or +15 over max for a Warbird.
After the power ends you are left with -30 power to all subsystems with a minimum of 5 in any subsystem that was below 35 to begin with.
You also lose you boff powers for 5 seconds.
You would recharge you power levels normally but your singularity recharge would not happen until all subsystems were at their -10 start levels or 30 seconds whichever is longer.
The 30 seconds would be affected by the T'Varo console but only if the -10 power levels had been reached so the longer would still prevail.
You could have the most devastatingly powerful alpha in the game at the cost of crippling yourself without cloak being the prey to your targets PvP teammate or have a second alpha chance with the cloak there to get you out of trouble.
It would seem to be the perfect example of the high risk, high reward Romulan philosophy at work..
These numbers and times are all subject to change and enhancement but the concept of these two abilities are what I'm trying to showcase here.