You also gain the ability to move+run+assault on a waagh

which can be a pretty nifty distance with a 12"inch move and fleet.
I suppose warbikers will should be kings of speed and dakka, while boarboyz should be just as tough and kings of closecombat?
didnt boarboyz get an improved armour save back in 2nd ed? you could easily have them keep the 4+ armour save I think (or T5 alternatively)
Just giving them +1 w (just talking durability here) is not enough to make them as durable as warbikers. I think you should either keep them at 1 w but with +1 toughness and a 4+ save, or give them a wound and either a 4+ save or +1 Toughness. With the toughness bonus they will be slightly tougher against most attack, but will still lack the jink save.
I like the idea of giving them a +1 strength upgrade and the shred on
HoW.
Maybe give them either move through cover or the ability to reroll failed dangerous terrain tests, as boars dont have long weedy legs like horses.
maybe boost their sweeping advance ability. either crusader (mechanic wise fluffy, but the name doesnt suit orks) or the ability to reroll the result of they dont catch the fleeing unit.
Have you considered a cyboar upgrade? While not that fitting for feral orks its an old upgrade from 2nd edition (alternatively for feral orks make it a pigdoks speshul fungus injection) something like giving the unit rage
USR or 1D3
HoW or hatred(everything!) or feel no pai, once per game.