I never gave much thought to the rogue type in 5th edition Tunnels and Trolls. Sure they could fight with any weapon and had the ability to cast spells, but their abilities in both were much less than warriors or wizards. The magical ability of rogues in particular always seemed to fall a bit flat to me. Sure they could cast spells, but they started with none and had to learn them from wizards that were forbidden to teach them to rogues. That means high prices. A single second level spell costs a wizard 500 gp from the Wizard's Guild. What would a wizard charge a rogue to teach him one on the sly? Rogues also did not have the ability to cast lower level spells at lower strength costs, use magic staffs or similar implements to reduce casting costs, or use spells higher than 7th level. This highly reduced the effectiveness of the few spells the rogue did manage to learn. In the end, a low level rogue was simply a poor excuse of for a warrior (in my mind at least), and certainly not the best choice for a solo delver. This was not likely to change until the rogue had amassed a significant amount of money to purchase some of the most basic first level spells.
But this attitude changed when I saw a 7th edition rogue in action during a play test on my upcoming new solo adventure. In 7th edition rogues get a new bell and a new whistle that make them rather formidable character types. First, rogues start with one first level spell. Now most players would probably jump at Take That You Fiend, but there are other first level spells that are much more effective and can lay waste to the best laid plans of a solo designer. One such spell is Hold That Pose. The second new feature of rogues that make them viable at low levels is the Roguery talent. Oh, how I hate the roguery talent. The Roguery talent is based on Luck. A Rogue gets this talent equal to Luck + 1D6. This score can then be used in place of any Saving Roll on Luck, Intelligence, or Charisma. That's three attributes covered by one score which is increased by an additional 1D6. Roguery is quite different from other talents which have to be used in specific situations. The Roguery talent covers any saving rolls based on any of these three attributes. This is incredibly useful in a solo adventure. Let me tell you, a certain rogue made off with a large pile of loot thanks to a high starting Luck and his Roguery talent.
So I no longer consider rogues a poor option as characters, at least 7th edition rogues. I'll just have to add three or four to my own stable of characters.