In addition to the lack of services over fairly significant portions of Rural Britain, the major cause of complaint will be those who get the current HD services on DTT, who wont get the new ones because of power level constraints despite their transmitter transmitting MUXES 7 and 8.
As this is only a stop gap measure, to drive take up of DVB-T2 receivers, in preparation to migrate
the current T1 muxes to T2, (another stop gap measure) in order to <cough> optimise UHF bandwidth, so that more spectrum can be sold off to mobile phone networks.
In short Ofcom won't rest until all
DTT has vanished, that's the end game here.
I wouldn't go to any effort to receive the extra muxes, it will be easier for most not
served robustly by them to invest in a Freesat box, which everyone will need long term anyway
(unless you're happy/able to watch TV via the internet)