The best scenario is that all the large players out there have deep IT expertise and can easily get what those new changes' pros and cons, but in my experience it is not the case. Rich people have totally another set of criteria in decision making
If we speak about SW in particular, I don't see it too complex to be understood by miners. The recent BIP65 rollover, which is a necessary step towards fully-functioning Lightning Network, is going very fast. Of course SW is a fair bit more complex than BIP65, I guess it shows us that miners either a) possess enough expertise to evaluate proposals; b) trust core devs' expertise. I'd prefer 'a', to be honest

They are totally different, SW is a redesign of bitcoin, while BIP 65 is a planned patch toward lightning network which is easy to understand since it is very similar to a clearing based solution. Lightning network make things more simple (combining thousands of transactions into one) while SW make things more complex (split one transaction into two chains)