I can't really speak to the impact of the Glorious Revolution - my focus is the English Civil Wars (my pedigree btw: MA thesis London in the Civil Wars ... Blah blah... Tower of London BA thesis English Radical Politics and Piracy) - but as to Cromwell's influence...

People put far too much at Cromwell's door personally (in my opinion), he was influential and did end up running the country, and trying out several different versions of what we'd recognise as democratic practices but these were firmly within the existing Parliamentary model, and relatively little of it was exclusively his doing.

In fact, these democratic-ish ideas were often more restrictive (less democratic) than the system England had in place shortly before and during the Wars - see Pride's Purge and the Nominated Assembly. They steadily reduced the number of participants in the process of government and in the end Cromwell was king in all but name.

Though to be fair these later actions were in sharp contrast to Cromwell and Fairfax's behaviour while leading the New Model Army. The Putney Debates are considered by many the "conception of English democracy" but while Cromwell was heavily involved the real instigators were men like John Lilburne and the Leveller (and other radical) Grandees who supported the rank and file. Frankly at the time with the position that Cromwell and Fairfax were in there was an element of 'its chancy to say no to a large army who you still very much need' in the Putney debates. Cromwell's son-in-law Ireton may well actually have been more influential in pro-demoracy terms at the debate than Cromwell himself.

The Levellers however and Lilburne in particular were out spoken advocates of democracy from well before the start of the First Civil War. It was these radical elements within the NMA that really pushed through the events at Putney and influenced events for a little time beyond. Before, that is, the end of the Second Civil War when their behaviour became more troublesome for Parliament than it was worth and much of the Army was disbanded or sent to the Irish campaign. I feel like they would have made more of a contribution ideologically than Cromwell himself.

But also do not forget that the United Provinces ran on a similar roughly democratic system to that advocated by many of the less radical Radicals, so Europe in general was no stranger to the concept, though that is beginning to stray outside of my area.

To answer your question plainly, Cromwell probably did more harm than good in the end in terms of his contribution to a democratic ideology, however in the heady days of what the more Marxist writers call the English Revolution the concept was alive well and being propagated wherever its advocates could find traction, and so was probably quite influential in a European context as Europe was certainly watching events in England closely.

The links I've included should give you a good sketch of the key events I've mentioned if you've never come across them before, but for more detailed info on the particulars I'd recommend:

Christopher Hill - The World Turned Upside Down, God's Englishman GE Aylmer - The Levellers and the English Revolution Pauline Gregg - Free-born John Austin Woolwrych - England without a King, Commonwealth to Protectorate HN Brailsford - Levellers and the English Revolution

Valerie Pearl's London and the Outbreak of the Puritan Revolution may be useful to you because it gives you a really detailed idea of how far the democratic ideal really extended on a practical level, at least in London, in the 1630s-40s.

Also Eric Hobsbawm's The Age of Revolution may be of use to you; it deals with a much later period (1789-1848) but does address the legacy which informed the likes of the French Revolution.