You must go to Rocklands (Bouldering) and Boven routes. Oudtshoorn and Montagu are also well worth a visit (i.e. try to go there too!).
Don't worry about heat, it sucks sometimes, but won't stop you having a good trip. The sun stays up for a long time in the Cape at this time of year so you can do early morning and late afternoon missions for the best sending temperatures.
You have an opinion, so do I. When these differ, please don't confuse your opinion with the truth, nothing is absolute.