It almost seems like a cruel joke that the universe would birth creatures with extremely curious minds and a sense of exploration and make the distances between stars too far for reasonable colonization. The speed of light is the ultimate speed limit and even then it takes years to get to the nearest star and moving at the speed of light also seems unlikely or practical. Why would the universe be so cruel to its creatures?
The universe is cruel. "What a book a devil's chaplain might write on the clumsy, wasteful, blundering, low, and horridly cruel works of nature!" as Darwin put it. There's no reason to expect otherwise. But it's an interesting question as to what laws of physics a designer might impose to aid exploration, so I'll take your question playfully in that spirit.
The speed of light limit doesn't actually stop you exploring the galaxy. From the point of view of the external observer, moving clocks slow down, so a space traveller going to another star would experience far less time as they approached the speed of light. From the point of view of the traveller, the universe moving past them would contract in length, shortening the journey. It's a basic exercise in relativistic physics to show that if you continually accelerate at 1 Earth gravity (from the point of view of the traveller) then the distance you can reach in a given experienced time increases exponentially. It only takes about 20 years from your point of view to reach the other end of the galaxy, 70,000 light years away. This is much faster than you could do it if relativity didn't apply and there was no light speed limit.
The thing is, though, that when you turned round and spent another 20 years coming back, you would find 140,000 years had passed back on Earth. You can go explore, but you can't come home again after. The only way to build a galactic civilisation is to have all of it continually on the move, at near lightspeed, so that they all experience the same time dilation.
There are other problems with relativistic travel - your fuel needs go up exponentially too, and running into dust particles or lumps of rock at the speed of light is bad news - but the lightspeed limit isn't a problem. And those other problems might have technological solutions too.
Time dilation does make the universe more suited to exploration than a Newtonian universe would be, but it also has the effect of preventing empires. It makes it hard for one culture to take it all over, and reduce the diversity of experience. Either you go and don't come back - the scattered colonies diverging along their own paths - or you stay continually on the move - only dropping in on static planetary civilisations every hundred thousand years or so. Either way, it seems designed to promote diversity and independence. Much more to explore!
And then of course we might be able to find ways to enjoy the journey, too. We could build dark planets that travel the void between the stars, kept warm and alive with cores of radioactive isotopes, and heavy insulation on the outside. There is nothing in the laws of physics that stops us from extending our lifespans indefinitely, either. So maybe one day we could enjoy a ten thousand year cruise between the stars.
There are inner worlds to explore, too. The laws of physics allow the world to be simulated using bits of the world itself. Virtual reality! We can create and build our own worlds and universes to explore, in computer games. The same physical laws that make intelligence and curiosity possible also make it possible to build worlds within worlds.
And finally, I would point out a pertinent feature of games is that they get boring if they are too easy to beat/win/complete. The difficulty and risk - the cruelty, you could say - is the point. We play games to practice for surviving real life, so it is no surprise they are similar, but this isn't the first time anyone has proposed that real life looks a lot like a game. And if you were designing a game you knew you were going to be playing forever, you would ensure that you could never run out of boundaries to explore. The universe is far bigger than we can encompass because it's meant to last.