I think you have to understand Types when working with Ruby. Otherwise it's just syntax voodoo.
That's a big part of what helps a language like c# continuously reinforce a mental model that leads to better/easier understanding. IMO.
You can call `open` and pass it a URL in Ruby. But what does that return? What's the Type? Where do I look up documentation for it? What's available to me _right at this point in my code_?
Ruby makes copying examples a bit easier, but you have to hold a lot more in your head before you could be considered "proficient".
And then there's all kinds of caveats. You want to write an O/RM in .NET? Pick up the PoEAA. You want to do the same in Ruby? Well, one of the first things I did was write DataObjects. Because there isn't a consistent database access API for you already.
From there you want to map Rows into Objects? Be prepared to play Ruby Golf. Because your first shot will be unusably slow. Not because it's wrong. But because it turns out Ruby's performance has real world implications. So you memoize anonymous classes. You cache method handles. You run a thousand different micro-benchmarks on the performance difference between re-binding a cached method handle for a setter, or just calling instance_variable_set.
I think the complete lack of type declarations actually makes developing in Ruby much more complex. Even experience programmers can end up debating wether a breaking change between "truthy" and an actual Boolean is a good or bad thing.
With as much experience as I have in Ruby, `extend` and the self class stanza are still just weird.
Even after developing in Ruby for years I'd still run into code that was just real difficult to understand how it worked at all.
I guess what it comes down to is I'd argue declaring all your method parameters as `Object` in c# is not going to make writing working code easier. It may make compiling easier, but that's not really the goal.
It sounds like you're a fan of Pry. I never cared for it personally. I found it much less intuitive than clicking in the gutter, running my program, and being able to mouse over a variable to see it's value, or look in a panel to see the full program state at this point. For a learning tool, I feel like that's got to be light years better than the solutions I've seen in Ruby. I managed that in c# without any help at all.
As far as exploring, Types generally tell me all I need. In Scala and IntelliJ I just hit ^J. Or I'll jump to the source of a method I'm calling with COMMAND+B. Or the implementation of an interface with COMMAND+SHIFT+B. These are just things I got out of the daily tips popup.
Seeing a function called: `generateDownloadUrl: Photo => String` tells me more in less time and space than the equivalent Ruby method or lambda ever did. Because in Ruby you don't know the requirements until you read the source or documentation. Whereas in Scala (which I wouldn't actually recommend to a beginner, but the same is true in c#) you have to resort to documentation or reading the source far far less frequently. Which for me at least is a much lower cognitive load.
Because of checked exceptions, switch statements and FactoryFactoryFactories I probably wouldn't suggest Java. But I think that languages that self-document the Types at declaration points are much easier to grasp than languages that still have the types, still require an understanding of them to be proficient, but omit those declarations (like Ruby). In Ruby you basically have to memorize a large chunk of the standard library before you feel proficient. The same isn't really true for Scala, Java or c#.
It's easier to build a mental model (for me) in those languages. And that's the biggest barrier to understanding and feeling like you grok it (at least for me).