They could have stayed within canon and still skirted the licensing issues. The ships had to be different, but not THAT different. No USS Enterprise, but the design parameters could have stayed more similar. Look at Voyager. It looks distinctly Federation, yet it looks nothing like any other starship in the Federation and it is the only ship in the Intrepid class we have seen. Defiant also looked distinctly Federation and looked like no other ship. The Enterprise 1701-D was a totally different ship and class of ship, and still looked distinctly Federation. These ships look sorta Federation, but the designs are too advanced and too different for the time period Discovery is supposed to be in. What they did to them does not qualify as an "update".
The writing was not strapped by licensing either. There did not need to be a Michael Burnham, and Sarek was unnecessary. And all the other extra crap they added into Discovery is a writing team gone amok and amped up on Starbucks. The spore drive, the windshield on the bridge decks of ALL the ships, the HUD displays and holograms, all could have been closer to canon. The uniforms could have been different colors. The Klingons did not have to be changed AS MUCH, but yes there was a licensing issue with them and the other prime timeline aliens.