Among other things, most of the early educational policies pre-dated the CCP's control.

He's often blamed/credited with simplification of characters and standardisation of the spoken language to the Beijing acrolect, but both of these predate his rule by some years.

1913 saw the creation of the Committee for the Unification of Pronunciation which in 1919 published the National Pronunciation Dictionary. This was not based on Northern Mandarin, and instead had a number of concessions to speakers of southern Sinitic varieties, such as preservation of the "entering" tone category (入聲) which was lost in the North. This new official variety was known as "blue Mandarin" 藍青官話 lánqīng guānhuà — "blue" here meaning "mixed" or "impure"— named the same as the former not-quite-natural but-kinda-Nanjing-style standard in use going way back into the dynasties.

However, due to a complete lack of native speakers, as in there were 0, in 1932 a new version of the Dictionary was published which was based on the speech of highly educated Beijingers at the time. In fact this too was not "pure" Beijing dialect, as the educated peole had already been long learning a more southern variety of Mandarin. So this was 1932, then officially in 1956 the PRC officially said "yeah we're continuing that".

Character simplification was also not Mao's doing. In 1935 the first major efforts by the Nationalist government were undertaken. Prior to that, during the Qing, there were still other efforts at simplification. What the CCP did was not hand out a bunch of new characters to people, but rather tell them "Okay, all these simplified characters you're all already using in hand-written texts are now official and will also show up in newspapers". The KMT's efforts to do the same failed in part because the 1930s weren't the best of times, and there were many more pressing issues to deal with, for example the Communists and the Japanese.

Having a Romanisation system was also not Mao's doing, or the CCPs. In 1928, YR Chao's (趙元任) system known as gwoyeu romatzyh 國語羅馬字 was officially adopted. It wasn't until 1958 that the current system, hanyu pinyin 漢語拼音 was adopted, replacing GR which many felt was a bit tough to learn. Pinyin offered the benefit of being able to completely ignore diacritics, as many in the MOE continue to do today. GR itself was replacing 1916's zhùyīn fúhào, also known as Bopomofo, and still in use today in the ROC.

The major change Mao actually wanted to do was get rid of characters altogether. This obviously didn't happen, and he eventually dropped it.

If you're super bored I did an episode of the AH Podcast on this topic, which gets into a little more depth and also addresses more generally what was going on in the rest of East Asia.

Further Reading:

• Baldauf, Richard B., and Robert B. Kaplan. Language Planning and Policy in Asia. Bristol, UK: Multilingual Matters, 2008.

• Zhou, Minglang, and Hongkai Sun. Language Policy in the People's Republic of China: Theory and Practice since 1949. Boston: Kluwer Academic Publishers, 2004.