To my knowledge, there hasn't been announced something specifically in that regard and PrestaShop themselves seems to have other focuses right now. Myself, I wouldn't put my hope in this.
Since performance of the site and especially cart operations & checkout is very essential, as it can really make the difference of several percentages of having more (or less if it's worse) sales, I would suggest to get a developer on board who knows to pin down what's causing such issues, knows to distinguish what matters especially in terms of browser performance, how to address them in the best manner and can solve them for you.
I've been doing that for almost every store I've been working on, always with great results and seeing my customers benefiting greatly from it 
In default PrestaShop there are so many things which can be improved in terms of performance, especially in the theme. This however hasn't been a priority or a concern most of the time for the PrestaShop team.