If you can't have a dumb couples fight, then are you really a couple? Only bland characters with no real personality (or hint of realism), would be like 100% perfect for each other all love, no play couples. They are also the most boring couple. Who needs a mister and miss perfect? Would you even really want to read that? The romantic turmoils that matter the most and give you the most emotional fulfillment are always the internal factors, not arbitrarily forced external factors (for instance, R&J, where all the challenges to love are external circumstances).
For instance, one of the longest running shoujos out there, Skip Beat, all the challenges to love are internal circumstances, that is, the characters themselves are the road blocks to love. That why you can see them grow and develop as characters to overcome internal strife, other wise known as character driven plot.
That's why, this super slow burn romance is better than... they like each other at the beginning and then get together. Its not the "ever after" part of romance that readers enjoy. No one cares after they get together. We care about the steps leading up to it. That's shoujo. Read stories and novels for adults if you want to deal with the trials and tribulations after they get married/get together.
Wait, where was I going with this again?
Oh right, I think this childhood friend aspect of the series is pretty cute. Instead of being lovey dovey friends, they are rivals who fall in love.