Not really. I believe it has stalled people's decision from moving to the Tamron. Just think of the noise we would be hearing if Tamron had their lens available cheaper than the existing Canon 24-70 mk1, having better image quality and with IS...and Canon had nothing new in the pipeline.
I believe Canon got wind of the Tamron lens and had to pre-announce well knowing they could not deliver for another 9 months.
In that case, i look forward to the announcement of a 10-2000mm F1.0L IS that weights 500g. Announced 2012, shipping 2050 when technology catches up. I don't believe announcing a product and then not being able to ship it helps. Lets compare the IQ of the Tamron and the Mk2 - oh wait we can't cos the Mk2 does not exist in a meaningful way.
Those people who are waiting would, on the whole, have waited anyway. Those who were minded to look for the best available lens will buy the Tamron - because it's available!! And what constitutes a reasonable timeframe between announcement and product ship - the 1DX saga (i'm still waiting despite ordering on the 19th Oct 2011) is simply outrageous. The fact is that Canon come across as being amateur and cynical in announcing a product and then continually slipping the date when it can be purchased.