Schefflera likes medium light conditions, and it sounds as if yours is getting medium light. Your plant is pretty tall, and can become lanky and less green at that height. Check the conditions under which Schefflera like to grow: average warmth, not below 55 degrees and not above 70 degrees; bright light but not direct light; lots of water, except in winter, with frequent light misting of leaves; no cold drafts. Have you repotted it every two years? That's important to the health of this indoor tropical tree.