I don't believe it to be completely 'average' either. It's not perfect, but there are more than enough excellent episodes in there - this is the season which gave us "The Chain of Command" two-parter, easily up there in my top Trek outings ever.
All I'm saying is... I'd argue that it's impossible for any
tv series not to exhibit some>
signs of tiredness by the end. Season 7 arguably even moreso than Season 6.