Absolutely. If you're anything like me, you'll fall in love with the landscape, the people, the towns, the stunning views, the factions and the add-on content. Don't treat Oblivion as 'that game that came before Skyrim', think of it as its own game within the Elder Scrolls universe. Appreciate it for its strengths, and you'll fall in love with it just like us
The modding community is still active - there's a steady stream of new mods, and they supplement the plethora of existing mods. The huge supply of user-created content ensures that PC users can tailor the game to their personal tastes - but I
strongly suggest trying the vanilla game first.
Exploration is ... Exploration. Everyone has their own opinion on the matter. I love exploring Cyrodiil, and can appreciate its dungeons for their unique layouts. I do believe Skyrim does a number of things better, but that doesn't mean I don't love exploring Cyrodiil.
Quests in Oblivion tend to vary more than in Skyrim - there are less dungeon dives and more unique quests - solving thefts, helping sons defend their farm, spying for an insane Bosmer ... But at the same time, I feel there are too few quests. There are less than ten individual quests (that is, not tied to a guild or questline) available in the Imperial City, which is the heartland of the Empire. Again, it's a matter of taste.
Really, just try the game for yourself, and make your own mind up. You'll have a blast!