I consider selective landwalk a huge miss. Unless your opponent doesn't play basic lands, this is unblockable, no need for learning keywords with awkward variables. That said, landwalk or unblockability isn't in white's color pie anyway.

reset him back to his original of just Plainswalk which is in White's colour pie, just as a secondary or even tertiary ability.

Works for me. Not too much precedent of plainswalk in general, so it feels cool.

I may be nitpicking, but White Knight and others set a precedent for 2/2 first strikers Knights with another ability. +1 toughness wouldn't this too powerful and it would make it fit under that model. But nothing really serious, though. Either is fine.

agreed