I was surprised and dismayed when my base was decimated due to enemy tanks rolling out of an ocean. I reasonably assumed that putting my back to the water would potentially expose me to naval units, but certainly not tanks. I'd be pretty disappointed if this was not a bug because (the realism of tanks driving through water aside) it makes the strategic selection of a coastal base nearly redundant. What are your opinions on this, perhaps a balance could be to allow travel through shallows only?
It's just a bug right now. Realize that early alpha doesn't really provide you with good gameplay. It's more a testing ground for finding bugs and abnormalities. Amphibious tanks/bots has been known since day 1, rest assured it will be fixed.
As somebody who has lost a navy to a hoard of Mirbots. I do think it would be cool if there were specifically designed hover-tanks and amphibious bots, but only as expensive T2 units.