How a 24-knot Dreadnought raises every fleet speed

Would a 24-knot HMS Dreadnought become the standard battle-line speed and force battlecruisers to go faster?

Yes; it would push battlecruisers toward 27-28 knots and raise cruiser and destroyer speed requirements as well.

A battlecruiser only one knot faster than the battle line cannot scout, disengage, or hunt armoured cruisers with the intended margin. If Dreadnought reaches 23 or 24 knots, the first battlecruisers must begin around 27 or 28 knots. Cruisers then need enough speed to remain useful around the faster capital ships, and destroyer requirements rise with them. One change in the fleet standard therefore cascades through the entire force rather than remaining a single-ship improvement.