DMG Marking

[Cheesegear]

Do you like it? Why/why not? Does it do its job, or work at all? Would you change it?

For the most part it does nothing, because Opportunity Attacks simply don't come up often enough for the bonus to be worth it.
Sentinel isn't good because it prevents movement, sometimes...Rarely.

Sentinel is good because it allows extra Opportunity Attacks, before the target makes an attack. That is, it causes off-turn attacks to proc, earlier, more often.
Sentinel is good because it hard-counters Disengage. That is, it causes more off-turn attacks to proc, more often.

Marking a target makes Opportunity Attacks marginally better, when they happen normally...Which they don't. Because DMs don't just walk targets away from you. They use Disengage or Flyby hostiles. Therefore...Marking a target is relatively meaningless. All's you're doing is providing another disincentive for the DM to make mistakes.

I attack...Miss...But I Mark the target.
Great. The Goblin Disengages as a Bonus Action and dives at the Wizard.
But I Marked...
Cool beans. It does nothing.

In conclusion;
Sentinel doesn't need the free buff. Please don't buff Sentinel even more.
Everyone else could use the free buff...But Opportunity Attacks are so rare (basically they only happen if the DM is incompetent or desperate) that who cares?

...It also buffs Melee characters with the Shield spell. Effectively allowing two Reactions per round...But again, it's still only more like one Reaction per round because Opportunity Attacks still don't happen. But IMO, I also feel like that Eldritch Knight should maybe just have the option to cast the Shield spell as a Bonus Action on their turn.