Almost every contest I participate, at the end I say "it was speedforces" and probably most of the experts too. And I thought, why is it the case? So I have a offering, but first I will talk about why I have that offering.
Contests have problem arrangement based on their difficulties. Even if the difficulty of the two adjacent problems were same, amount of people solved first is more than the second one. Thats because of the fact that people have less time every problem they solve. On top of that, the problems hardness increases, so most of the people I know (Including me) gives up when they solve an ok problem. And this makes a pile of people who solved the first x problem but doesn't have time + courage to solve the other problem.
So my offering is because of the fact that the number of people solved problems drops exponentially, making the problem difficulty gap less between C, D and E (maybe even same hardness). So contests may be less speedforces.
Last contest:
https://mirror.codeforces.com/problemset/problem/1815/A -1300
https://mirror.codeforces.com/problemset/problem/1815/B -2000
it is quite evident in some of the contest d problems in div2 and interactive ones too as even if they required basic binary search still no. of solves is pretty less.
Thats because people give up when they see they gain some points. But to reduce this contests may have easier problems.
Considering those problems are also in the div1, making them the same difficulty would make the div1 contest speedforces or at least not fun. Also, if they were to have the same difficulty div2 contests would still be speedforces, just with a different definition. If you make some problems the same difficulty that means participants have to solve all of them, which makes speed a higher factor than it is now.
What people normally call speedforces usually happens when there is a high difficulty gap between two problems that most div2 participants usually solve (which happens mostly with the problem D). The issue is, authors don't set the problems to make the difficulty gap like that. Even if you invite a lot of testers, it's still not easy to decide the exact difficulties of the problems. Usually, the problem order is decided based on the difficulties of the problems relative to other problems.
That's not how Codeforces decides the ratings of the problems. It's not a perfect representative of difficulty and gets affected by many things. For example, if the problem statement is too scary or it's an interactive problem (like your example), most div2 participants give up, hence making the rating of the problem higher.
Of course there are some contests where difficulty order is actually broken. However, in my opinion, it's not the case for most of the contests that get called speedforces, and making some problems the same difficulty definitely isn't a solution.
But when you have multiple mid range questions, people will have a chance to comeback after a bad start (slow start I mean) thus pile of people will not be the case. In my opinion the different definition of speedforces is better than what is now. It will also test your skill in different type of question making the testing better
Speedforces helps you solve problems faster. What's wrong with that?
The biggest difficulty is that it's hard for authors to precisely judge the difficulty of a problem, to within 100 rating points maybe.
Suppose that an ideal contest has problems with difficulty gap no more than 400, e.g. 800-1000-1400-1800-2200-2600. The authors try their best to make it this way.
However, not everyone thinks the same way, and what might seem easy to the author may come as unique and new to other participants. The reverse can happen: what might seem like an intuitive observation may end up being overrated.
As such, suppose that C was overrated by the authors by 100 points, and D underrated by 200 points — quite natural given the human nature of authors and random variance. Suddenly, we have a gap of 2000-1300 points, which is quite big and makes expert coders feel that the round is speedforces!
Authors aren't perfect, especially as they don't think the same way as the average participant does. It's unavoidable that sometimes their judgement doesn't match reality.
I mean, if problem E is around the same difficulty as C, the contest really becomes a div 4(and if all of them are relatively solvable it becomes more speedforces). I think most experts believe every contest is speedforces because they are on the cusp of solving D or E, since those problems are usually just out of reach in their rating ranges. I was hardstuck on solving a-c for a while but for an even longer time I would be stuck solving only a-b. Also, as someone who reads the majority of the problems each contest, I feel like too many people are too focused on solving problems chronologically. As seen in the last div 2, many people including myself found E significantly easier to solve in the time frame of the contest than D.
But there is still a pile of people who cant solve D but can solve C. You cant just unsee it. Also it makes specialist role more like slow experts.
Speedforces = problem X is too easy and problem X+1 is too hard. That's it.
Every contest can be speedforces to some people. There are just much more experts than people at higher ranks.