I hope not - as you appear to be saying - if you improve your site don't bother as you will be hit next month.
However , when you get an almost straight line graph of visitors/page views/ impressions( in WMT ) every time there is a change I am inclined to agree with you.
AS I posted elsewhere, it's almost as Google doen't want certain sites to get beyond a traffic level.
For example, Thursdays has always been, for us, for over 10+ years, a bad day. Now it's the best day. But Sunday/Monday, normally the best, is now the worst !
All I can see is throttle, throttle , throttle. Stop these sites annoying our advertisers.