At this time there are no intentions to raise minimum requirements to 7.4. Those on shared hosting have a limited selection of 7.2 capable-hosting as it is, the last time I checked. No need to make that even more difficult.
There is also no desire to move the framework to a completely strict typed system. Unless you've seen benchmarks that I haven't the performance gains from doing so are minimal compared to things like accessing the database, which would be one of my first choices for somewhere to optimize. PHP, as a language, is loosely typed and currently the framework takes advantage of that fact. If you want a strictly typed version there is another user on the forums that maintains a modified version, I believe.
