First I would like to quote some relevant passages from two books that deal with this issue. In the first movement of the Unfinished Symphony there is a clash so harsh that to-day the part is sometimes modified by changing the B natural drum to C sharp, or alternatively by using an extra drum. In the same movement the drums play on B and F sharp, when a G and D would seem more suitable during a full close in G major. In his Second Symphony Schubert frequently uses B flat in a chord of C Major. Whether one should alter the original score in such cases, on the grounds that early composers would have written differently had the full resources of modern technical improvement been at their disposal, is arguable.
Opinions are sharply divided as to the justification of amendments in standard works.
That the restrictions under which the older classical composers wrote for the drums resulted in defects in undeniable. With the additional clarity of modern timpani these dissonances are, to some, intensely disturbing. In the works of early masters there are also many occasions where the drums are silent, when had it been practical to employ them, there seems little doubt that a part would have been given to them. Whether an occasional dressing of this nature is disrespectful is arguable. There are many practising musicians who openly disagree with the purists who consider it sacrilege to tamper with the scores of the great masters.