Re: I'd try Linux mobile
Have not used the Samsung tablet much but have Samsung Android smartphones. Killing app is a rarity. Rebooting is unheard of (admittedly, a couple of times a year I forget to charge it, but that's probably WORSE as it's a hard-crash when it does that).
Not sure what you're doing differently, but I've not had that experience. With my old Galaxy Ace, yes, I ran out of space all the time. But that was because the space was so pitiful and things insisted on going on the internal RAM first even if you used apps to move them to SD later. And, yes, Facebook is one of the worst culprits - it seems to grow madly over time, requiring you to Clear Data and log back in. God knows what's it doing.
But I've deployed other Android tablets in schools and we don't have these problems either.
This Christmas, I went to my Italian girlfriend's family. At one point in the room there were three new Samsung tablets, four new Samsung phones, and whatever we had in our pockets (almost entirely Samsung). We were teaching people how to use some of them, but others had been using for years. I don't think we killed a single app or rebooted once, even with the kids taking over and installing every free app they could get their hands on.
As resident techy guy - even with a language barrier - I got called on for all sorts. But the tablets and phones never figured except to show people how to use them. I did have to fix two iPhones that had gone muppet, however. And nobody even had a Windows phone. Bear in mind that dozens and dozens of relatives and friends came and went over the period and they all know me as the techy guy who fixes things for them.
And, no, I've never rooted anything either. The biggest problems I've ever had with Android tablets were the cheap ones not coming with Play Store so I had to fudge an old APK onto them and then update.