The EU Commission is desperate to find levers of action on tax policy. That's also the reason for the procedure against Ireland regarding the Apple tax ruling (which, importantly, is based on state aid rules, not the tax policy itself as the latter is largely off limits for EU institutions). In general, EU institutions tend to err on the side of more harmonisation and here the case is straightforward. Uncooperative tax policy is rightly seen as a major economic and PR problem, undermining the whole project and the EU Commission is wary of being seen as condoning it.
But there is little appetite for any sort of tax harmonisation – beside the VAT rules that already exist – from member states (not only Ireland) because it is extraordinarily complicated, politically sensitive and many of them (including Luxembourg, Belgium or the Netherlands…) have crafted loopholes to capture some tax revenues from larger neighbouring states.