I had a few issues since last patch also, luckily it was on my smurf. Was in champ select and everything locked up and kicked me out of lobby, was 2nd time it happend in 1 day so lost 13 LP total from it. Not a huge deal because it is just a smurf, but I could see how this could be extremely annoying if it happens on someone's main. In about 6 years of playing this game this has happend less than 10 times in total so it isn't like it has been a problem and that I shouldn't queue up or anything.
On the flip side, Riot really has no way of controlling this. Crashes happen and hopefully the client update fixes this. They really can't do anything to make it so that no one loses LP from a crash because otherwise people could purposely crash their clients when they want to dodge. Your best bet, if you don't want to keep gambling with whether or not you'll crash, is to wait until next patch or after a hotfix and then see if you are continuing to have the problem. Could also do 10-20 normals and find out how often you are having the crashes and then use that to determine whether or not you want to queue up for ranked. Right now I'm getting it in about 1 out of every 20 games so I am not really seeing it as a big enough issue to stop playing ranked. I do stop playing ranked on an account for the day after the first crash so I only get the 3 LP loss.
As far as crashing and not being able to get back in game before the /remake, the only solution to that is to have a laptop on standby that you can log into and reconnect to the game on if your game crashes. The 3 minute window isn't always enough time to reconnect. Sometimes I'll try to reconnect and just get a black screen, soemtimes doing that 4-5 times will finally give me a proper loading screen. Sometimes I have to restart my client in order to get back into the game, and if I already tried doing 4-5 reconnects there is no way I can restart my client and reconnect fast enough to make it bef ore the 3 minutes so it is almost a better solution to just always close your client if you crash and start from the beginning.