Well, I just tore through Star Trek Enterprise and really only had two complaints. The title song being changed/sped up after season 2 when they should have just gone to a more fitting instrumental piece like you see in two episodes of season 4 and, well, the last episode itself. The desire/need to tie it into a random episode of TNG is disheartening at best and really disrespectful. I'm actually surprised that Frakes and Sirtis agreed to do it consider that the Next Gen crew was so annoyed with their first movie being tied to Kirk and the rest of TOS. (Also 12 years after that episode neither Frakes and Sirtis looked like their old characters making the ties to that episode even more confusing. Not to mention a serious disconnect in my eyes.
It really is one of the worst finales ever. Which is a shame because Enterprise deserved better. It also deserved more seasons but at the same time... I pretty much told the tales it needed to, it made connections to other Star Trek series, told the early days of Starfleet, showed the struggles of the Human and Vulcan relationship, showed the creation of the alliances that would form the Federation... And, well, it also showed why the Klingons from TOS had smooth foreheads. (We all know it was because of the simplistic special effects of the 60s and likely budget concerns but it told a rather good story for it anyways.)
Also, I think the story arcs of season 4 (and too a lesser extent the season long story arc of season 3) were really well done. Its a shame that TOS or TNG never got to enjoy them. Voyager certain would have been better served by them as it would allow them to better explain time between episodes. DS9 with its war sort of hit on it... but doesn't need it with it being a long war and they did a good job making it feel like it.
Lastly, I want to mention just how amazing of an actor Jeffery Combs is. He played three major characters in two different Star Trek series. Shran, an Andorian in Enterprise, and Weyoun, a Vorta often seen negotiating for the Dominion on DS9, and Brunt, a Ferengi on DS9 that was Quick's nemesis. He often steals the scene, and his work in Enterprise is no different, but I still think his best work was in the DS9 episode Treachery, Faith, and the Great River (S07 E06). Anyhow, I hope they find a role for him in either Discover, Picard, or the newly announced Strange New Worlds. (He also did an episodes of Voyager so he's been in three of the live action series.)
Anyhow, I guess I'll work on Discovery now... Though with only 30 episodes (I assume) of Star Trek left I'll likely slow down and not watch basically only one show but we'll see.