I think the issue is not that robots arent supposed to not have weaknesses its that a good design should have other things mean the weakness doesnt matter.

To take an extreme example - Aarons gyrate robot had card armour I believe but it wasnt as big an issue in that design because it would kill thigns before they got a chance to attack the armour.

At the opposite end of the scale, I designed Achilles progressivly improving with my losses to account for whatever took it out each time where practical. The result? If you include hypotheticals its had six places in the top 3 of tournaments, and ten heat wins. Yet after all that, just as in its very first fight it is going to suck on producing a damage score in a judges decision purely because it doesnt have the means to do it.

When I design a vapour, I design it to make it cool by my view. As a stat writer, your job is essentially to demonstrate and try to persuade the writer that its as cool and awesome as you think it is.

Perhaps its easier to think of them as limitations rather than weaknesses.