As for the example of ikkyo; now you are talking about skill - experience - understanding. And by that I mean not just your skill - experience - understanding as shite, but also that of your training-partners as aite. If done well it is not likely that aite can get up once he has been brought down with ikkyo. But getting up in order to try to lift shite is not a valid counter; it is way to dangerous for aite.
There are valid counters for ikkyo, but they do not involve muscle strength or the supposed advantage of weight. I suggest you ask your sensei about ikkyo and its valid counters.
If your partner ends up on the floor, it was a valid counter.
I'm fairly familiar with the "aikido-like" counters for ikkyo, as my teacher has examined them at length on many occasions. But for the purposes of this conversation, I'm more interested in the practical question of whether uke ends up on the floor and pinned, or not.