Unlikely; it has to meet the same requirements and regulations for climb gradients as other twins, and it's unlikely it would be THE main type operating out of London City if it was underpowered!Got the impression it’s rather underpowered.
It may be that the times you've flown in it, the crew were performing a reduced thrust takeoff to the maximum possible reduction, which is why it may have felt slightly "leisurely" compared to some. It's something common to all modern airliners - the performance calculations are done for every departure, using quite sophisticated software, and we'll tend to use the minimum thrust possible while still meeting performance requirements, the goal being to prolong engine life and overhaul times. It's pretty complex to get into here, but if you search the net for terms such as "derated take-off" and "assumed temperature", you'll find out more. Obviously, if you're in a small twin like the E190, you might well need full thrust on a short runway like LCY taking off towards the city, but if you're departing from a nearly 4km runway in Amsterdam towards nothing but fields and sea, you probably don't!
I'm not sure what they do on the E190; the A320 only uses the assumed temperature method ("flex" as Airbus calls it), where as on the 737 we combine de-rate and assumed temperature. I think the Airbus widebodies use both, but I'd have to ask a mate that flies them.