From the Pfalz D.III wikipedia entry, yes I know is wiki but the quotes are referenced.
German pilots variously criticized the Pfalz’s heavy controls, low speed, lack of power, or low rate of climb compared to the Albatros. The D.III slipped in turns, leading to crashes when unwary pilots turned at very low altitudes. Moreover, the Pfalz stalled sharply and spun readily. Recovery from the resulting flat spin was difficult, though some pilots took advantage of this trait to descend quickly or evade enemy aircraft.
This isn't the aircraft we have in game is it? As I've said the FM's of the more recent ROF additions seem to be more detailed than the earlier ones, the DIIIa was one of the first batch of aircraft released irc.
Edit.....
Just reading at the Aerodrome that the DIIIa took 15 mins to reach 10K, the Se5 took what, 6 mins? Although the Alb is a poor climber as well. There seems to be a general lack of info on Pfalz designs on the internet, what there is seems to be quite contradictory.