“Should I stay or should I go?” Should you stick to an all-too-familiar traditional CMS and “reap” the benefit of getting loads of much-needed functionality out-of-the-box? Or should you bid on flexibility, top speed, and versatility instead? In a headless CMS vs traditional CMS “debate”, which system best suits your specific needs?

Now, let me try and “guess” some of the CMS requirements on your wishlist:
 

• to have all the needed functionality “under the same hood” (a predefined theme, robust database, a user-friendly admin dashboard...)
• to be developer friendly
• to integrate easily and seamlessly with any modern JS front-end of your choice
• to “fuel” your website/app with high speed
   

Needless to add that:

You can't have them all in one CMS, either traditional or headless.