Well, the familiar is as you've said: it's disposable in many ways. It takes 1 hour to summon a new familiar and it obeys you no matter what. Furthermore, it's main purpose on the rules as stated seems to be exactly to allow them to explore certain places without risk as well as to cast some spells at a distance, as seen in the following parts of the spell's description:

While your familiar is within 100 feet of you, you can communicate with it telepathically. Additionally, as an action, you can see through your familiar’s eyes and hear what it hears until the start of your next turn, gaining the benefits of any special senses that the familiar has. During this time, you are deaf and blind with regard to your own senses.

Finally, when you cast a spell with a range of touch, your familiar can deliver the spell as if it had cast the spell. Your familiar must be within 100 feet of you, and it must use its reaction to deliver the spell when you cast it. If the spell requires an attack roll, you use your attack modifier for the roll.

So essentially, if the familiar seems to be pretty good at exploring things for the wizard, that's because it probably is. Mechanically speaking, the familiar is something that can work as an extension of the wizard, which can have some good role-playing involved. However the fact that the spell itself states no penalties in loosing the familiar (probably because the familiar will always be a low CR creature and 5e prefers to give smaller bonuses instead of bigger bonuses with big penalties associated) does mean its essentially a disposable aninal drone unless the DM intervenes.

Now, as for what can be done to prevent it from becoming too problematic:

• talk to the players.

If you notice the rogue is getting bummed out for not having as much of a chance to show his skill, talk with the wizard and the party. If the rogue is not feeling left out and the party likes to strategise how they'll deal with each enemy like some guy with classes in a Japanese animation, then probably there's no problem to solve other than that your dungeon has now been read like a book. The familiar cannot attack in any way, so the rogue still has meaning in assassination and attacking enemies first without being noticed. If you twist some things in the dungeon, maybe the rogue and the wizard's familiar can start going together if you organize the dungeon properly (the place has spaces only the familiar could go through, and sealed doors that must be unlocked, or maybe the familiar just sticks around in case the wizard wants to help the rogue with some familiar-friendly spells)

If you confirm it's a problem and everyone but the wizard is feeling bummed out and talking doesn't solve it, then try to interfere in game:

• remember that the familiar is an extension of the wizard in many ways.

This might an option you can adopt, however while I'm adding it here, I don't recommend to use it too much, especially not for the entire dungeon, because it risks making the familiar dungeon ruining shenanigan last much longer and put only the familiar in the spotlight, at which point the wizard will be the only one playing. If the familiar can cast some spells for the wizard, transmit its senses to the wizard and do the job for the rogue, it should also need to do some rolls. Sure an owl probably won't have to worry about triggering ground traps, but it shouldn't magically and instantly detect them either. In fact, a familiar probably should miss most of the traps that rely something heavy enough to trigger them unless it's actively looking and nailing it's perception checks. Furthermore, while a smarter enemy might ignore the random bat flying in the dungeon, it might start paying more attention if the bat is slowly flying around and spending a good portion of time hovering near the traps.

• remember the familiar looks like an animal.

A smarter enemy might start so suspect a familiar that's not acting like a normal animal would. However, some enemies, mindless or not, might attack the familiar regardless if they spot it. A snake in the dungeon ceiling doesn't care if the bat is a familiar or a normal bat, it's the right size and a good meal, especially since it's been hovering over a place for the past minute, same for a goblin or kobold that just spotted a delicious looking, cat-sized bag of food walking around the place (chase scenes might ensue).

• remer your players are just standing in a place outside the dungeon while it all happens.

While the familiar is mapping the dungeon (or trying to do so without dying), the players are standing there. Are they hidden properly? Are there scouts outside of the dungeon ready to detect them and send in a warning for everyone to prepare and rearrange within the dungeon? Remember that the wizard's body is basically defenseless so long as they're doing familiar shenanigans in the dungeon while not using his own senses. Furthermore, they might be standing in the same place for more that 2 hours if a familiar dies twice. Are they really so well hidden no enemies noticed then and decided to prepare an ambush?

• remember the familiar is not actually a beast.

Let's take another look at what the familiar is emphasis mine:

You gain the service of a familiar, a spirit that takes an animal form you choose: bat, cat, crab, frog (toad), hawk, lizard, octopus, owl, poisonous snake, fish (quipper), rat, raven, sea horse, spider, or weasel. Appearing in an unoccupied space within range, the familiar has the statistics of the chosen form, though it is a celestial, fey, or fiend (your choice) instead of a beast.

You're not summoning an animal, you're summoning an animal-shaped Fiend, fey or celestial, and while a Fiend might not care about others of its kind, maybe a higher ranking celestial or fey might not be too happy to discover the spirits of its kind are being made to suffer by some guy in a robe who doesn't like dungeon crawling.

• sometimes there are survivors.

Think about it: you're an orc, you see an owl flying within your den, looking suspicious but not enough that you'd do anything about it. Then a party of adventures destroys the entire place and you barely make it out alive, then you meet another orc and a bugbear who went through the same thing. Now because the wizard spammed familiar dungeioneering, the medieval not-so-sinister six are bulking up their forces and hunting them for revenge, becoming a major force the party needs to deal with. The problem? These guys don't discriminate and have traps and foes for nosy explorers of all shapes and sizes. Maybe you might want to send the rogue with your familiar, or move from your position as soon as it gets found and everyone goes on high alert.