Unfortunately, the next one will be a conservative, because they always alternate liberals with conservatives.
Well I think it is worse than that.
Realistically I can only remember 3 popes in my lifetime - Benedict was clearly very conservative and didn't just talk the conservative talk, he also walked the conservative walk.
But JP2 and Francis were portrayed as being modernisers, liberals so to speak. But this seemed to be all talk - the reality is that neither seem to have made any progress in actually modernising the RCC - so they were modernisers and liberals in name only.
And while the RCC trundles along in its unchanging conservative manner society moves on - typically in a much more liberal manner. Just think about attitudes towards women and gay people, as examples, now compared to 1978 when JP2 became pope. So perhaps in 1978 the RCCs position wasn't too far away from mainstream societal positions, but as the RCC refuses to reform and modernise the gulf between its rigid positions and societal norms grows ever wider.