Without getting too into it, I personally think Marx would be flattered, but be somewhat discouraged by some of the uses of his name and the related theories of all stripes, which originated not from him, and often long after he died (and I'm not thinking of any specifics here, except maybe some historical 'bad' national government examples especially).
As one who find's Marx's Capital (vol1) to be one of the best explanations of how capitalist theory works (which reads mostly like a history and dry economics book), I have yet to come across anyone in a public discussion of such concepts who was familiar with, what to me was, the most telling parts of the work - namely the chapter on historic labor laws.
There are no far-flung theories there, it is just a list of the first written laws by a government about labor, and his quips. Most examples are from like 1400-1600 (pardon all from memory here) and they include things like executing unemployed, brandings for vagabonds (*funny words abound), indentured servitude, etc.. Oh, and my personal favorite: the first wage laws were wage-MAXimum rules, where you could be punished for receiving a higher wage (the employer too but not so bad). It is an illuminating read from 1860's England, focused on the working conditions present (children's particularly in the post-slavery English factory economy). It also does highlight how a bit of femininity made a huge positive impact - in the form of Elizabeth I (late 1500's) giving some leeway to not punish child offenders so harshly, ushering in more liberal labor laws. My how I've simplified, but especially with that one chapter, anyone can get it..
That is not to say I don't like the core ideas of much of modern liberalism, even extreme ideas (I am barely familiar with the ins and outs of some of these schools of thought - so I do like reading things like this), but I'm not sure it really has that much to do with what Karl was really about in his time (of course this is how ideas form and change over time). I end up feeling like his original points were more valuable than we know these days, unfortunately because (as described in the article) the name Marx has been used since his death by such a breadth of different movements, and held in a negative light here in the US especially, sadly much to the woe of the poor...
**And to the point of economic versus social movements (like Marxism), I might say: sure they are certainly linked, but if we could actually make the significant improvements in the economic well-being of the all people, especially the poor (eg. improvements alluded to by Marx) we might find that the cultural advances continue to occur but in faster, more, and in better ways than they might trying it in reverse order.
PS. That all said, it is the actions that matter more than words anyway, so whatever has to be said to get it done - if it really makes things better for people, hey..go for it.