Pitch accent is not accent as in English, it's not any "the" syllable. If you've ever seen any of those videos about it, you'll see these down-up-flat patterns over the whole multi-syllable word. From high to low, from low to high, or low to flat plus/and other variations.

I wouldn't compare kanji to shorthand. Shorthand is typically not easy to read, normal writing is easier. Reading written, fully-spelled English is fast. Reading hiragana is slow (and I've been reading hiragana for a long time)- it's slow, and mentally much harder than reading with kanji. The only issue (and that is of course an issue, but tiny compared to Chinese) is that there's a lot to learn before everything can be read fluently. But reading only hiragana is just.. too hard, for any serious amount of text. It's not hiragana per se, it's the language itself with its limited set of phonemes which contributes to the difficulty.