Being tall-ish and having travelled on both there is definitely a very noticeable difference in seat pitch. Every row in the E190 has comparatively excellent legroom (comparable to "old" Club Europe), whereas every row in the E170 is quite tight. 30" on the E170 and 34" on the E190 sounds about right.
The reason for this is that the E190 has space for 46 (give or take) more seats than the E170, but BA only put an extra 22 seats in to keep the total pax count under 100 (Cityflyer couldn't operate it otherwise).