Every time someone mentions the Redhill rebuild it makes my blood boil! For what has been gained it was a total waste of money. Pretty much all London bound trains can still be accomodated in platform 2. The main user of platform 0 is the Reading trains so passengers now have further to walk to connect in or out of other trains. Platform 1 is basically the Tonbridge line bay platform. Given that the trains stop right at the north end, the Reading trains could use the south end of platform 1, which is exactly what they did before the rebuild.
The current morning peak service wouldn't have been possible under the old layout (although it is debateable whether an alternative service pattern could have run instead). The Gatwick / Reigate to Victoria trains join in platform 0 whilst a Horsham to Bedford train passes through platform 2 and platform 1 is occupied. At about 0739, platforms 0, 1 and 2 are all occupied:
Platform 0 by the Gatwick portion of the 0745 train to Victoria
Platform 1 by a Tonbridge train and a Reading to Gatwick service
Platform 2 by the 0739 Bedford service
The rebuild has also made platform 2 more accessible from the north when there is an issue in platform 3.
I agree that the timetable doesn't immediately appear to make the most of the work that was done.
However, getting this back on topic, if 3tph to Gatwick ever happens, the Reading to Gatwick and Gatwick to Reading trains need to be at Redhill at the same time and, given the current timing of other trains, that also does require the new infrastructure.
If the extra platform ever happens at Reigate and Bedford to Gatwick services get diverted to start / terminate at Reigate, the removal of splitting / joining at Redhill (ie running a Victoria to Gatwick stopping service via Redhill with no portions) will simplify platform occupation.