Ok, technically this has been an issue in Exp and Stable for a "Long" time across many updates. But I was surprised that I couldn't find a Bug tracker report, so I thought I should make one.
When moving with a pistol in hand, movement speed and changing directions in Heavily restricted! Seems to be around 15% slower sprinting with a pistol in hand, than with a huge rifle, from testing myself and friends have done.
And changing directions, running diagonally is slowed even more.
Generally, All movement is dramatically slowed and restricted when holding a pistol.