The status of paganism throughout the 4th century is very interesting, though it is a question that can be kind of hard to answer, and it depends a lot on what you define as pagan, secular and christian in this century, and different scholars come to quite different conclusions about it, but I'll try to say something about this.

First of all: My field of study is ecclestial history, looking at the growth and consolidation of christian thinking in the 4th/5th centuries, but that naturally also includes looking at pagan beliefs.

Let's begin: What defines a pagan? Before the 4th century, and even in the first part of it, there wasn't much to speak about a pagan identity, and in the time after Constantine even christian and pagan beliefs and culture were in close contact, to the point where we see bishops working hard to distinguish the christian identity so that christianity - now as the favoured cult of the emperors - would not just be assimilated into the broader Mediterranean culture/religious system.

In the middle of the century though, we see people (that is, aristocrats) define them selves as 'pagan', as a more defined identity, not just as members of their city's cult or the like. For the aristocracy this often went hand-in-hand with a focus on philosophy. Especially the aristocracy in Rome was known for its traditional (and thereby pagan) values, though the city would during the 5th century be established as a very christian city, but that's yet to come.

The emperor Julian is a prime example for this 'new' kind of paganism that grew in the middle of the century, inspired by the milieu that existed in Athens at the time. He took the role of patron of it, just like his predecessors had favoured christian cults.

So - how many people worshipped Roman/Greek gods? Here many scholars differ.

To begin with there's a lot more sources from christian writers than pagan: The christians got more and more 'brave' after Constantine and throughout the century, backed by the rhetoric of the empire. As the scholar MacMullen said: the christians made the most 'noise'. They enjoyed social superiority, and their religion was very much expressed in public; pagans on the other hand, at least in the explicit pagan rituals, kept to them selves. One might say that they lacked the 'social momentum'

So MacMullen argues that people worshipping pagan gods (that is, not necessarily adhering to the neo-paganism), were the majority even as late as 400CE, but we hear little of them, because the position of prestige rested in the christian groups. This could also be seen in the fact that cities were more christianised than the countryside.

Other scholars would disagree with these high numbers, arguing that MacMullen insists on a very 'harsh' definition of christian, implying that no 'pagan' rituals or traditions were adhered to by the convert, and thereby making a lot of people count as pagan. But no matter what estimate was, there was a lot of people who worshipped pagan gods in the time of Theodosius.

Were there any revolts? Certainly. The 490's were the decade with most tension between christians and pagans. It was calmer both before, where some kind of coexistence worked out, and later when it became clear that christianity got an even more dominant position. I don't know about the whole empire, but in Carthage there were both christian and pagan mobs fighting, and we have quite a few sermons from st. Augustine where he tries to calm down the christian crowd, and keep them from smashing idols in the pagan temples.

I know there were riots in Gaza, and I think more places, but unfortunately I don't have the sources to make the claim.

The riots in Carthage could take place as opposing sides fighting, but it could also be, as when the anti-pagan laws were relaxed, one-sided rioting from zealous christian groups who saw their militant behaviour vis-a-vis pagan temples as signs of them 'conquering' previously pagan land - 'showing' that the christian God was the one true God.

I hope I managed to answer somewhat close to your question, and that it's okay to read: Though I read english well, I'm not too used to writing in english.

sources: MacMullen, Ramsay: 'Christianizing the roman empire' Cameron, Averil: 'Christianity and the rhetoric of empire' Markus, R.A.: 'The end of ancient christianity' Brown, Peter: 'The rise of western christendom'