Cutesy exercises like glute kick backs, walking lunges etc have their place but nothing will ever replace the squat when it comes to overall leg development and size.
Master the squat and I PROMISE you will get the glute and leg development you are looking for.
Not a smith machine squat, not a hack squat, not a front squat, a real squat where the bar is resting on your traps.
Most people do not get the leg development they want because they don't understand the anatomy of muscles in the legs. The legs are an endurance muscle. They have a large composition of slow twitch muscle fibres. Most people only train in a 8-12 rep range. The problem with that is it won't stimulate the slow twitch muscle fibres. In order to fatigue the slow twitch muscle fibres, you need to train in a rep range of 20-100.
Use a variety of exercises to fully develop the legs but make sure to add in some 'burn out' sets at the end of your workout in a rep range of 20-100 to stimulate the slow twitch muscle fibre. You will feel a burn like you have never experienced before.
Think about it. Look at the legs of a cyclist. They don't squat or lift weights at all but they always have extremely impressive leg development. That's from all the high rep work they constantly do when cycling.