I won't tell anyone they should not solo dive ... but I will say that I think you shouldn't do it without knowing all the risks, and preparing for them through skills, training, and preparation. Otherwise, you're just gambling that nothing will go wrong.
Basic skills would include a basic level of comfort in the water, the ability to remove and replace your gear underwater, the ability to remove and replace a mask while hovering, the ability to make a free-water ascent and hold a safety-stop without assistance, and some basic knowledge about how to manage your air supply.
As to basic comfort, that's the main reason SDI requires a minimum of 50 dives before letting you take the solo diver class ... for most folks, 50 dives is about sufficient to start giving them the idea that there's an awful lot to this activity that they haven't had time to learn yet. They're starting to relax in the water and get comfortable with basic skills, but they've also gotten over the notion that everything they needed to know about diving was contained in their OW and AOW class. In other words, caution starts to set in.
Being able to hold a stop while replacing your mask is a pretty essential skill. Like it or not, if you dive often enough sooner or later somehow your mask WILL become dislodged ... perhaps even come off ... and you'll have to put it back on and clear it. Doing this essentially blind while holding your depth is not an option, if you start to ascend while putting your mask back on you run the risk of an uncontrolled ascent ... at some point the gas in your BCD will expand faster than your ability to release it, and then you ARE going to the surface.
Removing and replacing your BCD ... well, a likely place for an entanglement is around your tank valve/first stage, and without a dive buddy you'll need to untangle yourself. In this case, your only option will be removing and replacing your BCD underwater. Now, of course, most of us practiced this in OW ... but have you done it since? At depth? Without supervision? I'd recommend practicing it several times in the presence of a safety diver before betting your life on the fact that you could do it if you needed to.
Free-water ascent ... you'll need to manage your buoyancy not just on the way to the surface, but also during your safety stop. Can you do it? Have your practiced it? What about deploying a surface marker buoy? If you're diving in areas where there's boat traffic, that's something you'll want to learn as part of your basic ascent skills.
Air management is a requirement. Guess what ... if you suddenly find yourself low on air, your only choice is going to be an emergency ascent. So the obvious solution is going to be not allowing yourself to get in that situation. Developing good gas management habits is important for any diver ... the solo diver even more so.
Redundant air is pretty much essential, but make sure your gear-up routine includes checking initial pressure, leak testing, and a practice deployment before starting your dive. We had a death in our area not too long ago from someone (fairly experienced) who actually planned to use his pony for ascent, but neglected to make sure it could be deployed. It couldn't, and before he could manage the problem he drowned. Don't just assume that because you've got a pony bottle on your back you are "safe" ... there's a lot more to solo diving safely than just packing a redundant air source.
Just some things to consider ... if you think solo diving is for you, then go for it. Just don't take shortcuts. Take time to get some practice on your basic skills, assess your ability to deal with problems calmly (and be honest with yourself, your life depends on it), get some training, learn how to plan your dives properly ... and then assess your readiness ...
... Bob (Grateful Diver)