My story is similar but on a Seneca.
I do not find the single engine control of a Seneca an issue.
If I am not mistaking the EFATO climb rate of the Aztec as is the single engine max altitude. That's a serious downside alongside your benefit of load capacity.
Does your Aztec have a critical engine? Cos my Seneca doesn t.
Finally when i spend tens and tens of thousand of euros or pounds on a capital investment I like to have something that looks good, so I would always buy a completely repainted, recovered interior one, possibly including a new panel facia.
The Aztec is also showing signs of "vintage", that can be nice too