This is a variant that we like better than the original rules. Your mileage may vary.
(1) Nile cards go between desert tiles, not on top of them, so that the board is a full 5 cards x 2 cards (or 5 cards x 3 cards in the final round).
(2) Cube supply for 3 players: 13/13/14/14. Cube supply for 4 players: 10/10/11/11. (This accounts for the larger board, and lengthens the playing rounds usefully.)
(3) In Rounds 3 and 4, all excavation card values (the numbers on the card backs) are doubled.
These changes lengthen the game a bit, of course, but we like that. Especially with 4 players, 8 cubes per round goes too quickly for our liking. And we find that having cards score double in Rounds 3 and 4 increases the hard choices in the game -- saving cubes for later rounds becomes more important, but you still cannot ignore getting patrons early And Brown's power is diminished a bit because he is not (typically) as useful in later rounds -- but this balance sometimes shifts as players go after more patrons to control more land in Rounds 2 and 4 and thus there are sometimes late spaces left for Brown after all. With more cubes, Tangerine and Blackmore don't eat through your supply quite as quickly, but you still need to weigh their use in Round 2 and Round 3 versus saving cubes for Round 3 and especially Round 4.
If you have found Mykerinos a bit too short or sometimes a bit anticlimactic, give this variant a try and see if it breathes new life into the game for you. If not, well, no harm in trying, huh?