Kk, yes you have to minimize the lag at a few places so your server doesn't lag out and your players don't hate it.
Plus on my server players are within a small space, probs like 100-100 probs more idk, besides a few exceptions.
Sadly my server is whitelisted rn, but we have the map done, so it should be opened soon, im still working on getting everything updated to 1.2.
Keep in mind that server lagg isn't you're only problem. There's also network lagg, which is caused by the host's network having problems, a player's internet having problems, or the distance between the location of the host and the location of a player.
Mhm, I havent had any network lag that ive seen, up intill 1.2, but they supposedly "fixed" that in 1.2.1, but who knows ¯\_(ツ)_/ ¯
Well it's the network itself that causes that. No matter what version of the game you have, it's still possible.
1.2 increased the overall lag, like every new MCPE version does since they basically add features non-stop with thousands of bugs
It's a simple logic. The more the plugin your server has, the more the RAM is uses. I work for a network, that particular server has 2 RAM and has 50+ plugins and also an average of 50 players a day. I barely notice any lag or even crashes. Code: Heap memory: 5 MB. Total virtual memory: 2,048 MB. Total memory: 181 MB. Main thread memory: 48 MB. Thread count: 10 This clearly states the importance of "Thread" instead of RAM. The logic behind this something like a computer, whenever your RAM gets used 100%, your computer will switch to your drive for more memory. In this case, if you have a powerful SSD instead of a HDD. You life won't be miserable.
Yes, you said it in different way. I'd say that plugin which uses "Task" instead of AsyncTask may effect the server. The performance may be even terrible if all their plugin extends PluginTask instead of Async. We can conclude with 3 words which is "poorly programmed plugin".
Moving code to async task usually won't yield a direct benefit in performance, you'd be lucky to save a few hundredths of a second depending on what the operation is. Running big loops, queries or file reading/writing and parsing in an async task rather than in a plugin task is the only time you might see a noticeable performance increase.