Problem:
If I turn of Toolset View plugin and enable Toolset Blocks, will I have ability to play with my old views created under Toolset View plugin?
Solution:
Toolset Blocks is advanced version of Toolset Views plugin, you can activate Toolset Blocks plugin, it will deactivate Toolset Views plugin automatically, and you can still use classic editor to play with your old views by these:
Dashboard-> Toolset-> Settings-> General, in section "Editing experience", enable option "Show both the legacy and Blocks interface and let me choose which to use for each item I build".
Refresh the page, and test again.
Relevant Documentation: