And you want gear task specific in some respects. A smart phone screen can be a flashlight--and give you away--and distract you with apps. I would want gear that doesn't promote distraction.
Sure there is something to be said for devices capable of multi-functions, but then again there is something to be said about devices build to do one thing. A device capable of doing many functions has in theory more that can go wrong with it. So it makes sense to have more specialised devices that do one task very well, rather than several tasks ok.
I always did think the tricorder should also be useful as a communicator... especially in TNG+. After all, if the little badge is so capable, why can't that capability be incorporated into the tricorder body. How much bulkier would it need to be? And, yet, I can't recall ever seeing someone communicate via their tricorders. Now, I wouldn't replace communicators entirely with tricorder units, as the combadge is pretty convenient, but I would like to see the tricorder get this capacity also. --Alex
It's likely the Tri-corder has some sort of communication system build in to it. So when a ship is in orbit/nearby it can use its computer to help process the information.
The interface needs work. Mass Effect seems to have tackled that with the Omni Tools, which is basically just a holographic touchscreen that wraps around your arm. The omnitool itself is built into the user's clothing and/or surgically implanted in his arm and it basically functions as a combination tricorder/communicator/replicator/melee weapon. In Star Trek's case, it needs to be realized that your basic communicator is limited by the fact that it has no screen, no buttons, no real way to interact with it other than flipping it open and talking to it. The tricorder has the same problem: even the TNG version has no keyboard and the button layout is pretty limited. For both devices, I could see having a device that you flip open and it immediately creates a holographic display either in the air in front of you, or a virtual display that only the user can see (via contact lenses or implants or whatever). Communicators might even allow visual communication this way, and tricorders could -- through a lot of fancy touchscreen work in a holographic interface -- be programmed to do some pretty fancy things without the Trekian cringeworthy "push four buttons in seemingly random combinations" programming technique.
This comes up every so often. Regarding multi-use, I, for one, wouldn't want to command a crew that had sidearm/tricorder/communicators somewhere on their persons at all times -- especially since, in TOS at least, landing parties are so often separated from their communicators. Hopefully there is gun control in the 23rd and 24th centuries. And remember that we view it all on TV in 2-D. For all we know, bridge viewscreens and tricorders offer 3-D imaging. And communicators have Dolby surround! Anyway, when someone invents a cell phone that is able to transmit my coordinates down to the molecule, via "subspace," so that my body can be converted to energy for transport, without towers or satellites, and we have hand-held ray guns that can stun or vaporize, that combine handheld computers (in a pinch with some vacuum tubes and platinum) which can scan and deliver newspaper clippings from alternate timelines centuries ago, which can also scan spaceships in orbit from the ground, then yes, all Trek devices will be anchronistic.
Actually, it's been pretty explicitly shown in at least some TNG episodes that the viewscreen *is* 3D.
I always find it interesting to see how modern technology continues to head towards what Star Trek postulated as mere fiction 50 years ago. With each new development, I've always been able to turn to a friend and say, "Star Trek had all these things five decades ago you know". People keep mentioning Picard's desktop computer. One thing I found interesting that I'd never noticed before until a recent rewatch is how Patrick Stewart changed how he operates the prop as time went on, as technology like laptop computers started to become more mainstream. In the beginning he was just kind of gingerly tapping it's single button interface as if to imply that's how it cycles through options. But there's a point around the early 90s where he really does begin to operate it more like a real computer, using its single control button in a manner suggesting that he's moving a mouse pointer around the screen. Just a little observation, a case where Star Trek's future began to catch up with our present rather than the other way round.
Having a separate gun from your "phone" and sensor device makes sense. If you're firing it extended at arm's length from your body for accurate aiming purposes, then having to yell at something near three feet away in a combat situation would be impractical. And in a diplomatic or casual environment, if you had to go to what everyone in the room knew was your gun to call the ship, this could be socially unacceptible. Hopefully not. The future should at minimum have as many freedoms as we have now, and preferably more. But certainly not less.
Given that every civilian and their mother has a hand phaser of some sort with lethal settings, I don't think weapon embargos work very well in the 24th century.