I would seriously consider to remove Steam Workshop subscription checks on manually installed local mods. This way people who do not use any Steam Workshop mods but prefer the old fashioned way of downloading a modpack and installing it by hand can still use the Launcher to join servers without local mods being unloaded by the Launcher - resulting in people being kicked off servers.
As it is now the Launcher is a very poor product. All it does right now is force people to use Steam Workshop. It compares manually installed local mods with the Steam Workshop versions. It can't even tell if it is a manually installed local mod or not. It treats all mods as Steam Workshop mods. People therefore complain, and they actually have no right to, that the mods we offer in our modpack are out-of-date and are having signature mismatches while they are as current as the ones offered by Steam Workshop.
We then thought it had to do with the meta.cpp file missing. No, it does not. Because then we again see how poor of a product the Launcher is. Even with the most current meta.cpp file present in the folders the Launcher still nags about it having a signature mismatch. And to make the issue even more stupid, the Launcher actually shows the mod with the subscribe option in the mods required by this server section but lower it will still opt for unloading it.
Before anyone says it is our set up. No, it is not. Not on our server's end, nor on client level. We have members who used Steam Workshop before and even they said the way it works now is really bad. Up until a few updates ago we never saw this behaviour but somehow someone somewhere felt it necessary to force people into the usage of Steam Workshop. Well, newsflash, we will not and do not use it.
My advice, if you want people to start using the launcher for everything then at least allow those who opt for manual local mods that have nothing to do with any subscriptions on Steam Workshop to actually do so. At least make the Launcher so intelligent it can actually tell a mod it finds is indeed a local mod WITHOUT a Steam Workshop subscription and skip all the mumbo jumbo about mods required by this server etc.
You can't tell me this system does not know whether or not you have a Steam Workshop subscription. Stop offering people who do not want to use any of it to subscribe to Steam Workshop versions of mods they run locallly and wish to keep it that way. Stop unloading local mods because people are not using their Steam Workshop versions. I am sorry but you have quite some nerve thinking you can just shove something down people's throats.
Helpful? Yes, for some who are lazy. No, not for those who still use their own modpacks because they choose to do so but are not allowed by a very poor piece of software that can't even tell the difference. Harsh? Maybe. But there are enough people who want to see the same change I am asking for here.