Make it a plot hook, maybe. Include a spellbook in with some of the colonization supplies, only no one remembers it and it's not on any manifests, and there's something a bit off about it...
I like this idea. You could even let the wizard have the book ahead of time - his spellbook is supplied by the patrons footing the bill for the colonization expedition. All the spells he has are in his book ahead of time, level 1 to 9, choose wisely... If you wanted to be more generous than the 6 + 2/lvl, make it a function of his Int modifier. Either his Intelligence modifier straight up, or Int + d4/lvl if you are particularly generous...
I instead said that the 1st level wizard PC had stolen or was bequeathed his master's spellbook, and I said it had a certain number of spells per spell level. I then rolled half of them randomly and allowed the PC to choose the other half.
Yes, this is what I was going for...
Also, are the PC's
The Colonists, or are they merely the scouts, explorers and hired muscle for the colony expedition? If it is a full scale colonization, would there not be some specialist on the ship too? - a metal smith, bowyer, herbalist, etc. To over come the plate armor, magic weapon hurdle, perhaps the adventurers find a meteorite, a mithral or admantine deposit and bring it back to the smith for him or her to fashion into arms and armor. Maybe the meteorite possess some innate magical power.
You could mix up cleric domains and druid circles too. Perhaps some are more powerful in this new land, perhaps some have their powers diminished.