Not really. It’s harder to predict what the gamer’s initial experience will be, true, I’ve experienced it myself. Once the player overcomes the initiation barrier, his experience will be not dissimilar from that of the developer. We’re all human.
I can only speak for myself, and I develope games for the ZX Spectrum. Not ZX Spectrum clones (including the NEXT), nor ZX Spectrum emulators running on traditional computers, nor ZX Spectrum emulators running on touchscreen devices. I will try to accommodate all of them to a degree—and if necessary—but not if it requires breaking compatibility with the original hardware. It is unrealistic to expect a ZX Spectrum game to operate as though it has been written with a modern smartphone in mind.
Should be? No. Might be? Absolutely.
True, but it can easily go the other way. That’s what balancing gameplay is all about.
True for many other platforms, including modern ones. It’s neither here nor there. It’s up to you to invite more people to help you design, develop, and test your game. You’re free to release as many pre-release versions, or updates to the final release. Some developers prefer not to do it. Others are quite open about it. Neither approach is inherently good or bad. Ultimately, it’s the result that matters.
I partially addressed it in my first point. Unless it’s some cryptic puzzle-solving adventure game, where it is, indeed, not easy to predict if anybody other that yourself will get the clues (e.g. pour machine oil on a magic bean during a waning gibbous moon, jump up three times while standing 17 pixels to the left of the Dorky Idol statue, and feed the been to the blue pterodactyl), we’re all pretty much on the same level. It will obviously take a novice a little bit of time to get the hang of the game’s mechanics—controls, inertia, collision detection, enemy patterns, pace, etc.—but it’s not something unattainable in principle. In this regard, the developer is just a gamer with more gameplay time under his belt.
TL;DR: Design a well balanced game. Then you won’t have resort to enabling, or relying upon, cheats such as infinite lives, emulator snapshots, etc.