The market gauge of long-term Eurozone inflation expectations continue to fall to near record lows ahead of the ECB meeting
That basically tells you that markets aren't expecting much positives to come from the ECB so even a continued dovish tone from Draghi will do little to really inflict further pain in expectations as seen above.
Markets are already beginning to price in a 10 bps rate cut by the ECB by July next year and it's hard to see how Draghi can add to that as the central bank is going to reaffirm their stance i.e. forward guidance as per what we saw in April.
That said, there is reason for Draghi to be even more dovish with global trade tensions flaring up and core inflation in the euro area slipping below the 1.0% y/y threshold in May, after the April report was boosted by Easter seasonality.
I reckon those two factors could play a role in seeing Draghi adding to the dovish tones this time around but it's hard to see them disappointing markets when traders/investors have already turned the corner and are expecting the central bank to do the same.
The euro has been somewhat resilient though in spite of declining sentiment towards the ECB, so perhaps there is room for further downside there. But it's hard for that to materialise when the central bank is going to stick with the same message - more or less - that we saw in April, albeit with slightly weaker economic projections.
Going by that sentiment, it's hard to see the ECB and Draghi disappointing markets when markets are already rather disappointed to begin with over the last few weeks/months. However, should they communicate increased uncertainty about the inflation outlook, expect markets to jump on that and punish the euro.