I find it unusual how a particularly dextrous adventurer is unable to hold on to and keep still a target purely because they lack the strength to do so, when there are cases in real life where dexterity is, possibly, more important. I have tried to come up with a feat that I hope will combat this, but because Dexterity is often seen as a power stat in 5e I have introduced some limitations.
The feat is as follows:
You have developed skills that allow you to use your natural agility to hold a creature in place. You gain the following benefits:
• When making a grapple you can use Acrobatics (Dexterity) instead of Athletics (Strength) for the contested check.
• If you are grappling a creature that is a humanoid, you can use an action on your turn to restrain the creature, which requires both of your hands. This effect ends when the grapple ends. If either of your hands are removed from the creature while this effect is in place, to attack or cast a spell for example, the restraining effect ends.
I was also considering the following for this feat.
giving +1 dexterity
adding a restriction to humanoids in the first bullet point
removing the restriction on humanoids in the second bullet point
I am hoping that by requiring the use of both hands in the restraining step that this is feat would be found in more supporting builds, as opposed to the Grappler feat which grants advantage to the grappler on a successful grapple. I expect this feat to be more commonly used on monks than other classes, or possibly used in conjunction with a fighter's action surge.
A good answer will consider other feats, and may come up with scenarios in which this feat is good or bad. Comparing the design of this feat to others (such as crossbow expert's feature which allows all ranged attacks to work within melee range) would also be beneficial, although not required.