I had a similar problem with my kitchen faucet, only in reverse. The cold was flowing better than the hot. Then I discovered that the previous owner had installed a by-pass valve for the hot water heater and that it had become turned some what, closing down the flow. So I twisted it back back open and all was well. Here in Texas we really don't need to winterize (well maybe in Amarillo) like folks up north do. Anything below 65° and we turn on the heaters!...
....They say, when folks from Texas go to hell...they take blankets!
If you have a pressure regulator, you might try upping the pressure a bit....Or...consult your local Gypsy fortune teller!
Tom