Stealth does need a big update.
If there is ANYTHING in combat near you, you should just immediately go into combat mode, regardless of the current state your on (invisible, stealthed, ect). Then, if you are like 90m away from everything, you can just end combat and go back to real time mode.
Then, you should have to roll a stealth check every full combat round (after the lowest initiative). If you are within 20m of any stealth/invisible target, you have to break the Stealth DC roll. Then, within the same initiative, if the Cone of Vision passes over a stealth target, you receive another chance to do a Stealth DC roll check, but with some type of bonus (like +5 or something) as long as you can see in the lighting (ie hidden in the shadows, you need either a torch, Dark Vision, or some other light enhancing ability).
This would resolve all issues with Stealth along with giving some unique situational bonuses like, Cone of Silence makes all Stealth DC checks outside the Cone of Vision auto fail, giving a Perception roll bonus if you have better vision or a light source near the Stealth target and within the Cone of Vision, ect.
This is, like, so so easy to understand and to program, too. It's just simple states that you check against.
