You may consider two modes of operation: "lite" and "full". The Lite mode would be all the basic functionality. Consider such situation: I'm leaving the office for business trip, I'm in hurry and I realize I forgot to print one more drawing I should present to my client. So I run the computer (it's some minutes), then I open some CAD editor and I just want to print a single page and then close. This basic (or lite) mode could only give some core functions, let's say opening files that are read-only, so I don't need to wait to open all 3d-libraries, millions of fonts etc.
But I can also, for normal work day, start full mode application.
And by the way, please do not use for "full mode" something like "expert mode", "professional mode" etc. This makes me afraid that I'm not that expert and by touching something I can break it. "Full" mode can also be not applicable if it can be related to a shareware that for full mode you have to pay something. Perhaps "basic" and "normal" would be better.
And heading back to your question: this technique with splash screen showing the progress of running is good, but I always wish the splash screen is not "always on top" and it has minimize button and when the application finishes loading it doesn't receive focus, because during the start-up I may want to type something in a text processor and if I don't look at the screen I may not realize that I'm typing the text to another application.