Having no means of mitigating Covid when it emerged was just one of many aspects to it which made it such a terrifying prospect. There was also the limited treatment options, lack of understanding regarding transmission, pace of that transmission, any number of factors. And don’t get me started on the press coverage.
As for severity, I have read in more than one article suggestions by those who understand these things that, when new variants emerge, omicron has spread so far and wide, and so quickly, that those new variants are unlikely to be able to “bully” it so that it becomes less dominant. I’m sure Ethan will be quick to correct my understanding if it’s misguided, but I thought the experts all along have suggested that, as viruses continue to mutate, so they tend to become less severe. That is what we are seeing, surely.
New strains may well be a whole lot worse than omicron. But comment I have read, seen and heard suggests that is more unlikely than likely.
Viruses do indeed tend to become less virulent as they evolve but it depends. Viruses exist to replicate, so if they can replicate they will prosper. If they kill the host before they transmit, that reduces their ability to replicate and they can't really prosper, so for that sort of virus, it will survive better if it becomes less virulent.
Viruses that transmit before symptoms occur don't have that problem, so there is less selection pressure on them to become less virulent. Covid largely falls into that category, so we should not assume that further variants will be even weaker than Omicron.
This process of evolution is based entirely on random chance. Covid isn't "planning" its next step. If a variant survives better or transmits faster, it takes over just based on numbers or it being like a race. Omicron was always going to dominate because of its transmissibility.
The other thing is that Covid is a virus with two distinct clinical phases. Flu and the cold don't have these. One is the immediate respiratory, pneumonia, shortness of breath aspect that occurs early. Omicron is clearly less potent at that than Delta. The second phase is an inflammatory disorder (sometimes called a cytokine storm) where a bunch of chemicals involved in immune response are triggered and cause inflammatory damage around the body. This is usually what kills people, who die of heart failure, renal failure, multi-organ collapse. You probably remember stories about people who appeared to be recovering after a week or so, then had a serious downturn. That was the inflammatory effects kicking in. It appears that Omicron is also weaker at this.
However, this inflammatory aspect has another dimension, subclinical (asymptomatic) damage. Studies of recovered Covid patients have shown a concerning rate of effects in various organs, ranging from effects on the brain which could accelerate dementia, the liver and kidneys which could cause premature failure, the pancreas which appears to increase the risk of Type 1 Diabetes in kids, and hyper coagulability which could cause heart attacks and stroke.. This is the bit that worries me about Covid, and what I think you should try not to catch it until as late as possible. It is likely these effects are mitigated to some extent by immunisation, which dampens the inflammatory effects, but we don't really know. Even though these effects may appear small, on a population level it can be significant, and having a bunch of small risks in various organs adds up to a lot more risk overall.
Here is a link to a story about this issue.
Over time, most people will develop a complex and effective immunity against Covid, as we did with flu. This will be made up of immunisations, ideally a range of different types (heterologous vaccination), updated multiphase vaccines that are currently in development, some immune memory filled in from common cold coronaviruses and exposure to new and hopefully mild variants for which you have good immunity. At that point boosters may only be needed for older or immunocompromised people.