I think it's a great move forward to men can now take over some of their wife or partner's maternity leave, instead of the paltry two weeks they got before. And it should help employers realise that hey, men have babies, too.
But it's still pretty sexist. Because it can only be shared if the woman is employed.
In my own situation, I've got a DH who has been a SAHD for nearly three years while I work full time. When I start my next maternity leave, we can spend a whole year together, two adults at home, raising our three while they are small and a handful.
If I were a man working full time and had a DW as a SAHM, I'd only get paternity leave and would not be able to spend a year at home, supporting her and receive SMP.
So a SAHM is expected to just get on with it, but a SAHD can be supported for a year. (I should add I'm only able to manage on SMP because we have savings. I know SMP doesn't really support anyone meaningfully. By supported I mean the partner, not the state).
Why can't shared parental leave be taken together, anyway? I can see plenty of scenarios where it would be better for everyone if both parents were home at the same time for half a year, together, rather than it being only one or the other - always leaving one person to cope on their own.