You can doubt and speculate all you want. Because Blueprints can be backedup with an actual C++ code base you can build your entire game with blueprints, it’s fast enough for most games and even AAA games can leverage them. Like or dislike of them is not a quantitative metric.
Since there are games built entirely out of Blueprints any argument about it being functionally limited is false, at least in terms of game systems. Where blueprints are limited is editor extension and development as you must use C++ for that. My suggested workflow (and this is leveraged a lot other places) is your core is built in C++. Then your game play specifics are built in blueprints. For instance you should not build every item in your game in C++, just your base item, the rest are blueprints. You can also quickly prototype complicated behavior in Blueprints, then refactor it in C++. These are not new workflows, these are tried and tested patterns used for many many years in the software industry.
Can Blueprints become a cluttered jumble of lines and squiggles… Yes but programmers also have a similar problem “Spaghetti code” and it’s not just a problem with “GoTo” statements. Interfaces and S.O.L.I.D. Principals and Design Patterns can also make Spaghetti code, but if used wisely they are powerful tools for re usability and maintainability. We have developed best practices over the years to reduce spaghetti code and the same needs to be true for Blueprints. Loving or Hating Blueprints is pretty much a personal opinion. I personally feel they have their place and need to be used responsibly and be well documented just like any set of code you write. Just as you can tell the rookie programmer by the mess of code he or she writes, so too can you tell the rookie UE4 user by the jumple of Blueprint Nodes and connectors he or she jumbles together.
But ultimately I am wrong, because the decision to use just blueprints or just C++ or the combination of both is a personal decision on your part as the developer of your game. If you hate Blueprints, don’t use them. If you do not know C++, that does not mean your game will not be awesome or responsive. Wish you had a different scripting solution, there are a few of those out there including a Javascript scripting engine for UE4.
Finally I will apologize for lending my aid to the resurrection of this thread, I spotted it at the top of the list, and did not see there where 15 pages of postings to it before plotting down my thoughts on the original question. Live you learn.