Agreed. I mean if I rush knights at a time when my opponent has horseman, knights, spearmen, and c bowman....I'm going to curb stomp too.
So lets break down what could potentially make the cruiser overpowered. These are the areas we need to debate to justify the unit's OP status.
1) Its power in a tech rush. As stated above, if you rush cruisers and your opponents doesn't yet have the counters, they are in big trouble. The question is, how big? Is it "game over", "you will automatically lose a city" or "you are in a complete defensive war until you get a counter". A key question of that is also around the Corsair. If I don't have Ironclads, then I have Corsairs. Now clearly corsairs aren't meant to counter Cruisers...but can they delay or hold their own long enough to let you catch up in tech?
For example when Frigates first come out, I have used Caravels in the past to hold them off. Its certainly not as efficient as Corsairs by any stretch, but delays and sometimes even kills are possible. Can we say the something about Corsair vs Cruiser?
2) Does it have a counter? Ironclads are designed to be its direct counter in the water, and artillery serve later on as its counter on land. Do these units "do the job", or are cruisers too strong against them?
3) How strong is its land projection? Obviously with range 2 the cruiser has a dramatic gain over the Frigate in projecting force onto the land. But the second question here is, how does its CS measure up to land contemporaries? Does the cruiser kill land units and cities as efficiently as frigates did against units of its time, or more/less efficiently?
I'm enjoying this debate because its trying to define the edge of "defining unit of the era" vs "overpowered unit", and I think its a worthwhile debate to continue. So...continue!