Besides take down rifles I like finding guns with different open sight options and some were added with no intention of adding glass. Some are quite useful such as a full stock CZ 22lr with adjustable elevation for sniping turtles accross the pond. A simple looking Dumoulin battue sighted rifle in 270 offers more accuracy than the running game sighted rifle was designed for.
Our DG rifles are for the most part are used with the sights it came with so its a crap shoot if they are what might be the best for you for more than as a back up.
With all that said if I'm paying money or flying a long way for a chance at a buffalo, I'm using glass. They just offer flexibility that irons do not.
Especially with the true 1x scopes we have now and then to throw in the illuminated reticle, we are living in great times. I have used the 1-6 Kahles and 1-6 Swarovski and can only imagine what the new 1-8 Swarovski might be like on a 375 H&H. If you have not viewed through a true 1x scope with good glass it is something to add to your bucket list to do.