means probably we won't see any fixes in the MSO5k-8k line ...
As I sold my 5000, the 70000 wasn´t in mind but that were my thoughts too.
The MSO5000 came up as the cheapest way to buy the new rigol platform - And they won´t spend much more effort to polish it.
This came in my mind as a year after buying has passed and no significant firmware updates were in sight.
But I won´t leave rigol and hopes are lying on the DSO/MSO7000.
While the performance of the 7k is higher, the 5k has as its advantage it was done later (check the PCB silkscreen to see the dates) so some bugs where fixed in that platform.
In terms of software, I'm starting (but don't have the time yet) to invetarize the various MSO appEntries and try to 'cross-run' them. E.g. run the software from the MSO8000 on the MSO5000 shouldn't be a problem. The hardware platforms are super similar. The FPGA code IS different (the big kintex 7) but appEntry is a single compile for all platforms I think...
Same there and the answer of my question ( will the 7000 have the same (noisy) frontend as the 5000 ? Yes..) let me vending my 5000 and changing to siglent.
And what to say, in the first year appearing, there are two significant updates avaible which are not only fixing some bugs, also nice features on board.
This in combination with the much less frontend and much better UI let me never regret to have done the change.
Sad rigol, so sad. 
My guess is, that their engineering resources all went into the new DS70000 series ... I still prefer the rigol platform for some reason

But it's common isn't it? Release and forget...