You don't change a working formula. At least not just for the sake of changing it. The OnePlus 5 had a camera that didn't stand out, but at least had relatively sound reasoning behind it. We can't say the same about the 5T's.
The premise of the new camera configuration doesn't make sense on paper to begin with and unsurprisingly, doesn't deliver in real life either. Unless you look at this dual camera as a a setup meant to mainly deliver photos with depth effects - for that it does an admirable job; otherwise, it's as good as a single cam.
If you can put the whole dual-camera-that-isn't-all-that-dual conundrum aside, the OnePlus 5T is a fine smartphone at a very reasonable price - how the definition of that has evolved is a different topic.
A top-quality display is one thing the 5T has going for it, and it doesn't hurt that the battery can keep it powered for quite a while. And while premium materials have trickled down into the midrange, the silky aluminum body of the OnePlus handset wouldn't be out of place on a phone twice its price.
You can also call us fans of OxygenOS. It's the best of both worlds - stock Android ambience, but with extra features to make your life easier. Face unlock is a prime example - an old and buried built-in Android feature brought to life with just a little extra work. Well done!
While the OnePlus 5 is not strictly a viable purchase alternative to the OnePLus 5t since you won't be able to buy one once the 5T's hit the (online) shelves, if you do already have a OnePlus 5, hold on to it. It's worth pointing out that the 5T isn't meant to entice OP5 owners, at least not the way we see it. It's in most ways the same phone, and if anything, the older model's camera makes more sense.
In most markets, you'd probably be able to get a Galaxy S8 for as much as or a little more than a OnePlus 5T. That'll get you an IP rating, storage expansion, wireless charging, higher-res display, better camera - just one, but is the second cam on the OP5T really a selling point? It is if you want to do portraits with defocused backgrounds.
The LG V30 is a lot more expensive now, but we've seen LG smartphone prices drop considerably only a few months down the line making them amazing value purchases. The V30's wide-angle cam is pretty-cool, it's got wireless charging, QHD display, water resistance, and a microSD slot. If you're not in a hurry, you could give the V30's price a chance.
Another one in the list of 'more expensive but for a reason,' the Huawei Mate 10 Pro is already running Oreo, is water resistant, and has a dual camera setup that can make a case for itself. It's also a member of a rather exclusive club - it's got an IR emitter.
At a level playing field, price-wise, the Xiaomi Mi Mix 2 will give you a different kind of premium vibe - the cold ceramic one. The OP5T definitely has the superior display and better battery life, while choosing between MIUI vs. OxygenOS is an entirely personal preference.
A superb display in a trendy aspect ratio, excellent battery life, and fluid Android experience - is that enough to make up for an unimpressive camera performance and the lack of a few key flagship features? That would have been an easy answer if big-name phones hadn't gotten so expensive this year. If one of the pillars of a great smartphone collapses, the whole thing goes to pieces, right? Wrong - the OP5T has the price to prop it up. Value for money is the game, and OnePlus knows how to play it, and it's going strong with the 5T.