A ‘ready made’ portfolio that automatically reinvests dividends, rebalances, etc, like Freetrade’s answer to Vanguard’s lifestrategy, say, but cheaper! The underlying ETFs could be the cheapest that do the job, and could also automatically be chosen to reflect the users home currency.
I know FT will implement an ‘autopilot’ function someday soon, but this takes it a step further imo.
This could take the chore out of tending one’s own portfolio for the more clued up investors, but would simplify things for new investors - everybody wins 
I might finally be able to make FT my main broker this way 
Examples
Adventurous:
Developed & Emerging large and Mid cap VWRL 90%
Developed Small cap WOSC 5%
Emerging Small (and/or Micro) cap 4%
Frontier markets 1%
Cautious:
Global bond ETF currency hedged 90%
Cash 10%
(UK/Home AAA) Government bonds ?
(UK/Home AAA) inflation linked Govt bonds ?
Target retirement (Year 20XX):
This could start out as an adventurous portfolio and follow a glide path, ultimately becoming a cautious portfolio a few years before user’s target retirement year (20XX)
Impact:
ESG World equities (e.g. SAWD) 80%
‘Green’ Bond ETF (e.g. CLIM) 10%
Sustainable Energy ETF (e.g. INRG) 5%
Gender Equality/Diversity ETF (e.g. ELLE) 5%
…or something similar, i’m sure you get the idea