I seriously doubt there will be upgrade of RAM or screen. 4gb and 12′ are already huge specs for a low end tablet. If there is again hardware, that’s would be for existing bugs like the failling motherboard in the first windows version. But it seems now to be fixed.
As for your concern about Remix os, i can say the OS is perfectly stable [on my teclast x98 plus] and already relatively mature considering the first version . And remix os add a real plus in the perspective of multi-tasking. Once you’re used to it, you don’t want to come back to stock android, which i found immature for tablet use even if adapted for phone.
The only downside is the lack of ability to add widget on the home screen. But some tweaks may allow to add a third party launcher like Nova Launcher in order to enjoy widgets.
My 2 cents.
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