Not really. I don't want to become a divemaster, not sure i could really dedicate enough time to that. I could become 'master scuba diver' but as far as i understand it Is just a honoric title. I am simply trying to become a good diver. Until now i took specialties that are necessary to do that certain dives: nitrox deep drysuit etc. Now i was trying to understand what experienced divers would judge useful and what not completely necessary
Within PADI and SSI Master Scuba Diver is just an "honorific title" like you suggest...under NAUI it is a specific course of instruction and certification. Outside of my initial openwater training, the NAUI Master Diver course was probably the most valuable dive related training I have participated in. But I will note that I believe the quality of training is based on the instructor...I just happen to have an excellent instructor who was very thorough and demanding.
If, as you state, you are "simply trying to become a good diver" then go out and dive more, taking classes and obtaining certifications in specialties does not necessarily make one a better diver.
Dive in a variety of environments and conditions, vary who you dive with and look at their skill sets critically, think about your own skill set critically, make changes to what and how you do things as necessary. When diving with more experienced divers request a dive debrief for to get constructive feedback. Reflect on the information you are given and compare it to what you already know. Try to learn something from every dive no matter the time length or depth, log it/journal it. Endeavor to exit the water a more competent confident, and capable diver than when you entered it.
-Z