Push your musicians to the limit?

Yesterday I performed (as a singer in the choir) in the performance of Symphony #9 by Beethoven in the Concertgebouw with the following line-up.  Cappella Amsterdam (professionals) supporting the VU Kamerkoor (amateurs), the Orchestra of the 18th Century (of course the best professionals) and soloists Katherin Dain, Esther Kuiper, et etc, all led by Jonathan Darlington.  

First off, generally speaking I was extremely happy with the professional, empathetic, vigorous, musical, and precise conducting by this gentleman.  Finally!  I conductor who can do it all, and that with a healthy and friendly attitude.  

The singers were invited to join the O18 because they were hosting a Beethoven Festival.  They had an absolutely gruelling schedule of daily rehearsals of various pieces and three evening performances in a row:  day 1 Beethoven 1 and Violin Concerto, day 2 Erioca and the 5th piano concerto, and day 3 the 9th Symphony.  We, of course, only joined for the 4th movement of the 9th.  My observation, having heard this orchestra in collaborations numerous times, was the following:  they had a very amicable and yet powerful musical bond with this particular conductor (I've seen them hate a conductor as well).  The musicality of the strings, timpani, and some winds, including the fabulous 1st bassoonist just bloomed under his direction. In particular I have to mention the 1st violin section, which under the leadership of Alexander J. was technically and musically impressive.  It was a huge Beethoven, raw and over the top where needed, emotionally vulnerable, without boundaries. 
The 1st and 2nd movements of the ninth were the height of their passions, abilities, and technique. 
And now I get to the "however."  The third movement I attribute to a management blunder.  The embouchure and concentration of winds and perhaps also conductor were struggling with fatigue.  Intonation, which I have a high ability to forgive in such circumstances, became an unavoidable irritation.  The 4th movement rekindled the energy and brought the symphony to a roaring standing ovation.  However, that 3rd movement still bothers me.  The O18 is simply a fabulous orchestra that under this particular conductor, could have sounded at their very best.  I think that the  management needs to analyze how far they can actually push these musicians without compromising quality.  A full rehearsal day on the same day as a concert of the 9th, after a long full week and two concerts of different repertoire is simply too much to ask of the wind's embouchure and the concentration of all the players and, let's not forget, the conductor!  

The orchestra is embarking on a new path, and many great steps are being taken to ensure the future of the orchestra.  To that, bravo!