You will no longer need to change at Dalston Junction for services to Richmond/Stratford. Just stay on train one more stop to Canonbury.

Highbury and Islington is great for the Victoria Line to Walthamstow Central or as an alternative to Kings Cross St Pancras without waiting 10 mins for a H&C train at Whitechapel.

There's also the National Rail First Capital Connect services from H&I (Mon/Fri except late evenings) which run to Moorgate, Old Street, Finsbury Park and up to Herts.