Suburi bokuto are a fast route to tennis/golferās elbow!However staying with the topic of swinging a weight around to develop striking strength perhaps doing regular kendo suburi but with a heavier wooden bokken could do for it ?
I think the idea is that of you can make a nice cut with a really heavy bokuto, using a much lighter steel sword or bamboo stave, will be much easier. I think it feels that way for the first few swings but the effect soon wears off. Modern weight training is a much better option.