Well, i have told you both that i create my cards uite conservative, because of which we had quite a few balancing discussion. In any case, the developer always tweaks the numbers and stats when adding a card to the game (My concept of ancient city for example hadn't the legend keyword, now it has).
Well,i resent against Mechos changes because of the following: All three positive effects (Summoning the rare, stock increase and damage) have a horrifical high cost to effect-ratio for a mixed cost uncommon.
Even the summon devil mode is incompareable with scepter of summoning because devil itself has one of the most ridicilous unconditional cost to effect ratio in this game (only matched by damnation,Implosion dragon squadron or bahamut, but like devil these cards got a very high cost which is a condition for itself)
The only thing which makes these ratios on this card justifyable is the fact that this card can backfire. Either in turning this card into something useless (like an imp) or by going out of hand (e.g. -40 tower).