Game companies have to pay the bills, just like any other company, and we all understand that. These F2P/P2W games always favor a paying customer over the non-paying customer, and that's appropriate. Some decisions, however, are unwise or ill-considered. Sketches is both.
Unwise decisions cost the company in the bottom-line. Ill-considered decisions do, too, but they are a long-term effect that often doesn't elicit a cause-and-effect line drawn between them due to the length of time between the cause and the effect.
Sketches are nice. You can upgrade many things in your home city with them. I don't want to address every possible upgrade, so I'll just concetrate on one. An upgraded acropolis can protect your supplies from raiding. It isn't much, really, when you consider the amount of resources needed for later upgrades. The raiding of home cities already terrifically favors a spending customer. The paying customer can buy in seconds what a grinder takes a month to build, and that's only after the grinder has been playing for months since a beginning player doesn't have those build options. Hence, a paying customer almost always wins in PVP contests, and when wars break out between players the non-payee almost always loses. Now that paying customer can protect their supplies even more. They can steal resources from the non-paying customer and the non-paying customer cannot take them back because the paying customer's acropolis holds so much more. In the just the first sketch upgrade the amount protect is 7k of each resources. This is incredible when you consider that the previous 20 levels combined could only protect 18k each. And this level of protection os only available to the paying customer. There is currently no way for a non-paying customer to reasonably gain the same advantage. Yes, placing in tournaments can earn you drachmas with which to purchase these sketches, but even doing well in tourneys only nets you hundreds of drachmas, and that's not the same level of competition the paying customer advances at.
I think I'll just stop there. The way money affects this game is the proverbial snowball effect. Once again, I get it that a business thrives on paying customers. The thing that I think attracts a lot of players to this game, though, is the huge amount of players to compete with. If the non=paying customers are pressed out of any reasonable competition then they will leave. That, in turn, takes some of the draw that paying customers like...the big game feel.
I could be wrong. I'll come back and check in a year or two and see how Plarium is doing.