I think it could be a way to prevent argument's that gangs do it on the less populated server although it limits the game play for others as during peak times gangs will be fighting over who's doing it, but that doesn't solve the issue of meta gaming where people join to defend their base or to join the HM just for the gun fight removing role playing from the equation and going back to the argument that it is meta gaming in the first place it would have to be maybe put to a vote if the majority is happy with allowing information to be given via team speak and hop on squads being allowed or not as before these rules were put into place and with what had been happening it was just a black and white example of meta gaming, at least if it was Server one it would max out and 20 cops wouldn't be able to flood in at once like they did/have been, or allow it on both, and any Police that join a server with an ongoing operation have to wait 30 minutes before they can move in and help with the operation in that way it can at least be looked at that 'Armed response' were called for and they were getting ready and the first cops were struggling so reinforcement's were needed, it allows the initial gun fight to go ahead and then gives some form of role-play towards these hop on squads and for everyone to be quick and get everything out before the next wave comes.
I personally think everyone should be allowed to go back after the NLR timers are up or Cops shouldn't be as sometimes I have killed the same cop 2-3 times in a single HM and its a bit silly/unfair that they are just coming back and challenging me again using previous information, this coupled with a cool down before joining an ongoing operation, would be a good solution but that's just my opinion.
The permission to raid gang bases is going to put so much extra work onto staff or remove game play of bases being raided there should have to be X amount of gang members on to raid the base, some form of initiation, and someone inside.