A faster Nelson could have changed the Denmark Strait force

If the Nelson class had been designed for 27 knots or more, might one have deployed with Hood against Bismarck?

Possibly; a worked-up Nelson might have accompanied Hood in place of Prince of Wales and brought reliable systems plus nine 16-inch guns to the action.

Faster ships are more likely to be assigned forward, so a 27-knot Nelson could plausibly have joined Hood. Unlike the still-working-up Prince of Wales, an older Nelson would have entered the battle with known systems and established routines. Its nine 16-inch guns could therefore have made Bismarck's engagement substantially more difficult.