I like it! Looks like a lot of fun!
First of all, love that you give several options for features at two different levels. In my opinion, regular choices (even nested within other choices) are one of the best parts of A5e, and I love it when people lean into that.
Requiring Pact of the Blade—how necessary is it? You grant proficiency with martial weapons and you allow Eldritch Blast to be used in place of weapon attacks for maneuvers. Removing that restriction could allow for many more theoretical builds and character ideas.
Mortal Mark: Love this feature! In my opinion, giving a creature disadvantage to your combat maneuvers for one minute
period might be a little strong. (Just going off of my gut.) Maybe have the effect end after the target creature fails a save against X number of maneuvers, rather than having disadvantage against every maneuver you do for a minute?
Since warlocks tend to have low Strength and rarely focus Dexterity, their maneuver save DCs will probably be lower than the average martial, so this feature might make Eldritch Disturbance the go-to for Bladesworn warlocks even with a small nerf.
Unearthly Vigor: Now that you can use your spell save DC in place of your maneuver DC, I definitely think Mortal Mark needs a little limitation, since most warlocks will have this DC at the highest they can get it just by focusing on being a warlock.
Blasting Blade: Now that's fun!

Fighters might be jealous that you eventually get more melee attacks than them, but you also have worse AC and HP, so I think the trade-off is fair.
Foretell Doom: Possible rewording, "You may cast Eldritch Disturbance as a bonus action on your turn. You may not do this and cast a spell (including a cantrip) or Eldritch Blast using your action on the same turn. When you cast Eldritch Disturbance as a bonus action, you deal half damage, rounded down."
Overstep: Does this feature intentionally allow you to learn a maneuver of any tradition, or is it intended to just work with the traditions you know?