It is definitly not hard to switch versus chargers of any kind. usually you can see pretty well when and if he's gonna charge you.
The problem is that you will need quite some hits and your opponent will 1-2 hit kill you (I know that this can take some time with dodge skills and maxblock).
Always make sure you _walk_ and dont run (like someone else here said) because it reduces block immensely, even if you desync less.
If he namelocks you, desync wont help a lot anyway.
As soon as he uses Holy Freeze, I would say that the bowzon is effed.
i have actually found more success with running, since if your frw is high enough, the charges won't actually land on you because you'll be up and out of range by the time the ax comes down. then if you throw in desync (especially from the kb from bolt/lf), it actually makes it very hard for the paladin to hit you.
i personally have found that when i run/throw back lf/lb, i only get hit once out of maybe every 15 charges. usually, because i throw back lf/lb so often, by the dynamic of the stop and go, the paladins charge hits you while you're throwing, meaning you have 75% effective block.
so i general, i find running + frequent stops to throw > walking vs. charge.