i am not sure of this is what you mean by realistic sparring
i spent many years in karate before comng to aikido, I still go and play with the karate oy sometimes and try to throw in some aikido if we have agreed it is ok before hand
i have notice many of the same thing as you mentioned, it can be difficult to do a techniques of a 'tester jab' but it is a different sort of fight, outside i wouldn;t be softing up people with jabs so much as going in to do as much damage as possible and so would my opponent at the time i guess
on attcking, yes many many aikidoka need to leanr to attack better, I sometimes (depending on grade) start really going for the attacks, sometimes bobbing and weaving before hand so i don;t telegraph the punch, really changes the feel of the training
It really worries me that so many martial artists think that a 'street thug' or 'angry attacker' is going to always be a rage blinded idiot who just runs at you throwing wild haymakers trying to kill you. It worries me even more that not only do they think this, they absolutely count on it.